Williams Libraries

Citing Sources: Chicago: Notes

The Williams Honor System requires you to properly acknowledge sources you have used in course assignments. This guide provides basic information on how to cite sources and examples for formatting citations in common citation styles.

Chicago: Notes/Bibliography

About Chicago: Notes/Bibliography

The Chicago Manual of Style Notes/Bibliography system is used by scholars in history, arts, and humanities. For social sciences and sciences disciplines, see the Author-Date system.

This style consists of two parts:

  1. A superscript number in the text and corresponding note
  2. A bibliography

See How to Format Notes, How to Format the Bibliography, and the examples of types of sources in the left navigation for further details.

How to Format Notes

For more detailed information see Chicago Manual of Style, 14.14.

A note consist of two parts:

  1. A superscripted note number (1) in the text, placed at the end of a sentence or clause
  2. A note containing the citation, placed either at the bottom of the page (footnote) or at the end of the paper (endnote).

General Formatting of Notes

  • List in order the author, title, and facts of publication
  • Author's names: write in normal order (e.g., Julia Alvarez)
  • Titles: capitalize in headline style (e.g., How the Garcia Girls Lost Their Accents)
  • Books/Journal Titles: italicize (e.g., How the Garcia Girls Lost Their Accents)
  • Article/Chapter Titles: enclose in quotation marks (e.g., "Black Twitter? Racial Hashtags, Networks and Contagion")
  • Separate elements with commas
  • Enclose facts of publication in parentheses
  • Abbreviate editor/edited by (ed.), translator/translated by (trans.), volume (vol.), edition (ed.)

1. Tom Nairn, Faces of Nationalism: Janus Revisited (London and New York: Verso, 1997), 17.

2. Craig H. Roell, "The Piano in the American Home," in The Arts and the American Home, 1980-1930, ed. Jessica H. Foy and Karal Ann Marling (Knoxville, TN: University of Tennessee Press, 1994), 194.

For additional examples, see the source types listed in the left navigation.


How to Format Subsequent Use of the Same Source

For more detailed information see Chicago Manual of Style, 14.24-14.29

  • If a note uses the same source as the immediately preceding note, use Ibid. in place of all the parts that are identical.

    1. Tom Nairn, Faces of Nationalism: Janus Revisited (London and New York: Verso, 1997), 17.

    2. Ibid., 39 - 43.

  • If a note uses a source that has been fully cited previously, but not in the immediately preceding note, shorten the citation using the author's last name and shortened title.

    1. Tom Nairn, Faces of Nationalism: Janus Revisited (London and New York: Verso, 1997), 173.

    2. Gilbert Geis and Ivan Bunn, A Trial of Witches: A Seventeenth-Century Witchcraft Prosecution (London: Routledge, 1997), 100.

    3. Nairn, Faces of Nationalism, 176.

    4. Geis and Bunn, A Trial of Witches, 105.

How to Format the Bibliography

General Formatting of the Bibliography Entries

For more detailed information see Chicago Manual of Style, 14.16; 14.56-14.67

Bibliography entries are formatted similarly to notes, with the following differences:

  • Authors: names are inverted (e.g. Alvarez, Julia)
  • Publication details: not enclosed in parentheses
  • Elements are separated by periods, not commas
  • "Edited by" and "Translated by" are written out, not abbreviated
  • Entries are arranged alphabetically by last name of the author.

Compare the bibliography and note forms for this book:

Bibliography:

Nairn, Tom. Faces of Nationalism: Janus Revisited. London: Verso, 1997.

Note:

1. Tom Nairn, Faces of Nationalism: Janus Revisited (London: Verso, 1997), 17.

For additional examples, see the source types listed in the left navigation.


Order of the Bibliography Entries

Chicago recommends alphabetizing using the letter-by-letter system, in which an entry for “Fernández, Angelines” would come before the entry for “Fernán Gómez, Fernando” (d in "Fernández" comes before G in "Gómez").

How do I deal with ___?

Missing citation elements

  • Author:
    • If no personal author is listed, determine whether an organization is responsible for the content. If so, use that organization's name as the author. (CMOS, 14.92)

      1. World Bank. Poverty and Social Exclusion in India (Washington, DC: World Bank, 2011), 15.

    • If the author is unknown, start the note and bibliography entry with the title. (CMOS, 14.79)

      2. "The Titanic Sails To-Day," New York Times, April 10, 1912.

  • Place: Use n.p. if it is unknown. If it can be surmised, put in brackets with a question mark. (CMOS, 14.138)
  • Publisher: If unknown, just use place and date. (CMOS, 14.143)
  • Date: When the date of a printed work cannot be determined, use n.d. For web pages, use the access date. (CMOS, 14.152; 14.245)
  • Page numbers: For unpaginated works, such as online resources, include a descriptive phrase using one of the divisions used in the work (chapter, paragraph number, section heading, etc.) in the notes. If the work is short, such locators may not be necessary. (CMOS, 14.17)

More than one author

  • List authors in order they appear on title page
  • In the bibliography, invert the first author's name only and place a comma before and after the first name
  • Use the word "and," not an ampersand (&)
  • For works with 4-10 authors, list all names in the bibliography, but only use the first author's name followed by et al. for the note.
  • For works with more than 10 authors, only include the first 7 authors and et al. in the bibliography
    (CMOS14.76)
Examples

Notes:

1. Gilbert Geis and Ivan Bunn, A Trial of Witches: A Seventeenth-Century Witchcraft Prosecution (London: Routledge, 1997), 17.

2. Chih-Hung Ko et al., "The Associations between Aggressive Behaviors and Internet Addiction and Online Activities in Adolescents," Journal of Adolescent Health 44, no. 6 (2009): 600.

Bibliography:

Geis, Gilbert, and Ivan Bunn. A Trial of Witches: a Seventeenth-Century Witchcraft Prosecution. London: Routledge, 1997.

Ko, Chih-Hung, Ju-Yu Yen, Shu-Chun Liu, Chi-Fen Huang, and Cheng-Fang Yen. "The Associations between Aggressive Behaviors and Internet Addiction and Online Activities in Adolescents." Journal of Adolescent Health 44, no. 6 (2009): 598-605. 


Using a source quoted in a secondary source

It is always better to consult the original source, but if it cannot be obtained, cite the original source and the secondary source you used in the notes and the secondary source only in the bibliography (CMOS, 14.273):

1. Theodore Sedgwick, Thoughts on the Proposed Annexation of Texas to the United States (New York: D. Fanshaw, 1844), 31, quoted in Lyon Rathbun, "The Debate over Annexing Texas and the Emergence of Manifest Destiny," Rhetoric & Public Affairs 4, no. 3 (Fall 2001): 479.

Rathbun, Lyon. "The Debate over Annexing Texas and the Emergence of Manifest Destiny." Rhetoric & Public Affairs 4, no. 3 (Fall 2001): 459-493.

 

Examples: Books, Chapters

Book

For more information see: Chicago Manual of Style, 14.68-14.169

Format

note:

1. Author First Name Last Name, Book Title (Place: Publisher, Year), Cited Page(s).

bibliography:

Author Last Name, First Name. Book Title. Place: Publisher, Year.

For e-books, include the provider of the book or the URL at the end of the citation. (CMOS,14.166-14.169)

Examples

1. Tom Nairn, Faces of Nationalism: Janus Revisited (London: Verso, 1997), 17.

2. Ellen K. Feder, Family Bonds: Genealogies of Race and Gender (Oxford: Oxford University Press, 2007), 44, ProQuest ebrary.

3. K. J. Stewart, A Geography for Beginners (Richmond: J. W. Randolph, 1864), 186, http://docsouth.unc.edu/imls/stewart/stewart.html.

Feder, Ellen K. Family Bonds: Genealogies of Race and Gender. Oxford: Oxford University Press, 2007. ProQuest ebrary.

Nairn, Tom. Faces of Nationalism: Janus Revisited. London: Verso, 1997.

Stewart, K. J. A Geography for Beginners. Richmond: J. W. Randolph, 1864. http://docsouth.unc.edu/imls/stewart/stewart.html.


Edited Book

For more information see: Chicago Manual of Style, 14.87

Format

note:

4. Author First Name Last Name, ed., Book Title (Place: Publisher, Year), Cited Page(s).

bibliography:

Author Last Name, First Name, ed. Book Title. Place: Publisher, Year.

Example

4. Basil Dmytryshym, ed., Imperial Russia: A Source Book, 1700-1917 (New York: Academic International Press, 1999), 35-41.

Dmytryshyn, Basil, ed. Imperial Russia: A Source Book, 1700-1917. New York: Academic International Press, 1999.


Chapter or Essay in Book

For more information see: Chicago Manual of Style, 14.112

Format

note:

5. Author First Name Last Name, "Chapter/Essay Title," in Book Title, ed. Editor First Name Last Name (Place: Publisher, Year), Cited Page(s).

bibliography:

Author Last Name, First Name. "Chapter/Essay Title." In Book Title, edited by Editor First Name Last Name, Inclusive Pages of Chapter/Essay. Place: Publisher, Year.
Example

5. Craig H. Roell, "The Piano in the American Home," in The Arts and the American Home, 1980-1930, ed. Jessica H. Foy and Karal Ann Marling (Knoxville: University of Tennessee Press, 1994), 194.

Roell, Craig H. "The Piano in the American Home." In The Arts and the American Home, 1890-1930, edited by Jessica H. Foy and Karal Ann Marling, 193-204. Knoxville: University of Tennessee Press, 1994.


Entry in a Reference Book

For more information see: Chicago Manual of Style, 14.247, 14.248

Format

note:

6. Reference Book Title, s.v. "Entry Title."

bibliography:

Well-known encyclopedias and dictionaries are usually cited in notes only. For other reference works, cite as a book.

Example

6. Dictionary of American Biography, s.v. "Washington, George."

Examples: Articles

Journal Article

For more information see: Chicago Manual of Style, 14.180, 14.184

Format

note:

1. Author First Name Last Name, "Article Title," Journal Title Volume, no. Issue (Year): Cited Page(s), doi: Digital Object Identifier.

bibliography:

Author Last Name, First Name. "Article Title." Journal Title Volume, no. Issue (Year): Page Range of Article. doi: Digital Object Identifier.

For electronic journal articles, if a DOI is not available, replace the DOI portion of the reference with the URL.

Examples

1. Margaret Hunter, "Colorism in the Classroom: How Skin Tone Stratifies African American and Latina/o Students, " Theory into Practice 55, no. 1 (2016): 58, doi: 10.1080/00405841.2016.1119019.

2. Maxine S. Thompson and Verna M. Keith, "The Blacker the Berry: Gender, Skin Tone, Self-Esteem, and Self-Efficacy," Gender and Society 15, no. 3 (2001): 340, http://www.jstor.org/stable/3081888.

Hunter, Margaret. "Colorism in the Classroom: How Skin Tone Stratifies African American and Latina/o Students." Theory into Practice 55, no. 1 (2016): 54-61. doi: 10.1080/00405841.2016.1119019.

Thompson, Maxine S., and Keith Verna M. "The Blacker the Berry: Gender, Skin Tone, Self-Esteem, and Self-Efficacy." Gender and Society 15, no. 3 (2001): 336-57. http://www.jstor.org/stable/3081888.


Magazine Article

For more information see: Chicago Manual of Style, 14.199, 14.200

Format

note:

3. Author First Name Last Name, "Article Title," Magazine Title, Date, Cited Page(s).

bibliography:

Author Last Name, First Name. "Article Title." Magazine Title, Date.

Inclusive page numbers are not included in the bibliography entry because magazine articles tend to appear on non-consecutive pages. If citing an online magazine, end the citation with the URL.

Examples

3. Scott Spencer, "Childhood's End," Harper's, May 1979, 16.

4. Héctor Tobar, "Can Latinos Swing Arizona?," New Yorker, August 1, 2016, http://www.newyorker.com/magazine/2016/08/01/promise-arizona-and-the-power-of-the-latino-vote.

Spencer, Scott. "Childhood's End." Harper's, May 1979.

Tobar, Héctor. "Can Latinos Swing Arizona?" New Yorker. August 1, 2016. http://www.newyorker.com/magazine/2016/08/01/promise-arizona-and-the-power-of-the-latino-vote.


Newspaper Article

For more information see: Chicago Manual of Style, 14.203-14.211

Format

note:

5. Author First Name Last Name, "Article Title," Newspaper Title, Date, sec. Section.

bibliography:

Newspaper articles are cited in the text in the notes, but usually are not included in the bibliography. (CMOS, 14.199) Below is the format, if required by your professor.

Author Last Name, First Name. "Article Title." Newspaper Title, Date, sec. Section.

Page numbers are not included because articles can appear on different pages in different editions. For regularly occurring columns, cite with both the column name and headline or just the column name. If citing an online newspaper, include the URL at the end. If citing from a library database, include the database name.

Examples

5. Steven Erlanger, "Pact on Israeli Pullback Hinges on Defining Army's Role," New York Times, May 8, 1998, sec. A.

6. John Eligon, "One Slogan, Many Methods: Black Lives Matter Enters Politics," New York Times, November 18, 2015, http://www.nytimes.com/2015/11/19/us/one-slogan-many-methods-black-lives-matter-enters-politics.html.

7. Martin Luther King, Jr., "Negro Faces Dixie Justice," My Dream, Chicago Defender, April 23, 1966, ProQuest Historical Newspapers.

Eligon, John. "One Slogan, Many Methods: Black Lives Matter Enters Politics." New York Times, November 18, 2015. http://www.nytimes.com/2015/11/19/us/one-slogan-many-methods-black-lives-matter-enters-politics.html.

Erlanger, Steve. "Pact on Israeli Pullback Hinges on Defining Army's Role." New York Times, May 8, 1998, sec. A.

King, Martin Luther, Jr. "Negro Faces Dixie Justice." My Dream. Chicago Defender, April 23, 1966. ProQuest Historical Newspapers.

Examples: Web Pages, Blogs, Social Media

Web Page

For more information see: Chicago Manual of Style, 14.245

Format

note:

1. Author First Name Last Name, "Page Title," Website Title, last modified Date, URL.

bibliography:

Website content is usually cited in notes or in the text only. (CMOS,14.245) If a bibliography entry is needed, use the format below.

Author Last Name, First Name. "Page Title." Website Title. Last modified Date. URL.

If there is no personal author, start with the page title or site sponsor. If there is no last modified date, use an access date. 

Examples

1. Norman R. Yetman, "An Introduction to the WPA Slave Narratives," Born in Slavery: Slave Narratives from the Federal Writers' Project, 1936-1938, last modified March 23, 2001, http://memory.loc.gov/ammem/snhtml/snintro00.html.

2. "Maps of State Laws and Policies," Human Rights Campaign, accessed July 27, 2016, http://www.hrc.org/state_maps.

Human Rights Campaign. "Maps of State Laws and Policies." Accessed July 27, 2016. http://www.hrc.org/state_maps.

Yetman, Norman R. "An Introduction to the WPA Slave Narratives." Born in Slavery: Slave Narratives from the Federal Writers' Project, 1936-1938. Last modified March 23, 2001. http://memory.loc.gov/ammem/snhtml/snintro00.html.


Blog Post

For more information see: Chicago Manual of Style, 14.246

Format

note:

3. Author First Name Last Name, "Post Title," Blog Title (blog), Date.

bibliography:

Blog posts are usually cited in notes only.

If the blog has the word "blog" as part of its name, "(blog)" should not be included in the citation. If the blog is a part of a larger publication, include that title, too.

Example

3. Jenell Stewart, "Natural Hair Creates a More Inclusive Standard," My Natural Hair Journey (blog), Huffington Post, July 12, 2016, http://www.huffingtonpost.com/jenell-stewart/natural-hair-creates-a-more-inclusive-beauty-standard_b_10949874.html.

 


Blog Comment

For more information see: Chicago Manual of Style, 14.246

Format

note:

4. Commenter Name, Timestamp of Comment, comment on Blog Post Citation.

bibliography:

Comments are usually cited in notes only.

If the blog post has been cited previously, the blog post citation can be shortened.

Example

4. Silver H., August 16, 2014 (3:17 p.m.), comment on Jack Halberstam, "You Are Triggering Me! The Neo-Liberal Rhetoric of Harm, Danger and Trauma," Bully Bloggers, July 5, 2014, https://bullybloggers.wordpress.com/2014/07/05/you-are-triggering-me-the-neo-liberal-rhetoric-of-harm-danger-and-trauma/#comment-9001/.

 


Social Media

It is nearly impossible for the Chicago Manual of Style to provide examples for citing every new social media platform, but you may find advice or examples on their Chicago Style Q&A or CMOS Shop Talk. When there is no specific example, look for similar types of sources and use your best judgment to provide enough information to your reader about the source. Some elements to consider:

  • Who created the information? (could be a real name, pseudonym, or handle)
  • What kind of information is it? (e.g., Twitter post, Instagram photo, Facebook comment, etc.)
  • When did they post it?
  • Can your reader find it online?

The answers to these questions can be incorporated into a sentence in your text or you could create a note using the general formatting guidelines for notes.

For an example of Twitter see: Chicago Style Q& A, FAQ 164.

Examples: Music, Film, TV, Images

Music Score

Published music scores are cited like books and book chapters. For more information see: Chicago Manual of Style, 14.269

Format

note:

1. Composer First Name Last Name, "Song Title," Book Title, ed. Editor First Name Last Name, (Place: Publisher, Year), Cited Page(s).

bibliography:

Composer Last Name, First Name. "Song Title." In Book Title, edited by Editor First Name Last Name, Inclusive Pages for Song. Place: Publisher, Year.

Example

1.Charles L. Johnson, "Crazy Bone Rag," in Ragtime Jubilee: 42 Piano Gems, 1911-21, ed. David A. Jasen, (Mineola, NY: Dover Publications, 1997), 42.

Johnson, Charles L. "Crazy Bone Rag." In Ragtime Jubilee: 42 Piano Gems, 1911-21, edited by David A. Jasen, 41-45. Mineola, NY: Dover Publications, 1997.


Music Recording

For more information see: Chicago Manual of Style, 14.276

Format

note:

2. Composer, Performer, or Conductor First Name Last Name, Album Title, Record Label Catalog Number, Year, Medium.

bibliography:

Composer, Performer, or Conductor Last Name, First Name. Album Title. Record Label Catalog Number, Year. Medium.

Example

2. Virginia Eskin, Fluffy Ruffle Girls: Women in Ragtime, Northeastern Records NR 9003-CD, 1992, compact disc.

Eskin, Virginia. Fluffy Ruffle Girls: Women in Ragtime. Northeastern Records NR 9003-CD, 1992. compact disc.


Film

For more information see: Chicago Manual of Style, 14.279

Format

note:

3. Film Title, directed by Director First Name Last Name (Original Film Release Year; Place: Studio/Distributor, Release Year of Medium Used), Medium.

bibliography:

Film Title. Directed by Director First Name Last Name. Original Film Release Year. Place: Studio/Distributor, Release Year of Medium Used. Medium.

Example

3.Thelma & Louise, directed by Ridley Scott (1991; Santa Monica, CA: MGM Home Entertainment, 2004), DVD.

Thelma & Louise. Directed by Ridley Scott. 1991. Santa Monica, CA: MGM Home Entertainment, 2004. DVD.


Online Video

For more information see: Chicago Manual of Style, 14.280

The format of citations depends on the information available. Generally, include details about the original published source (if applicable) and details related to the digitized copy such as source type, length, and where it is posted. See the two examples of format below.

Format

note:

4. Video Creator First Name Last Name, Video Title (Original Production Company, Original Release Year), from Provider of Online Video, Source Type, Running Time, URL.

5. "Video Clip Title," Source Type, Running Time, from Original Performance or Source, posted by Name of Person/Organization, Date Posted, URL.

bibliography:

Video Creator Last Name, First Name. Video Title. Original Production Company, Original Release Year. From Provider of Online Video. Source Type, Running Time. URL.

"Video Clip Title." Source Type, Running Time. From Original Performance or Source. Posted by Name of Person/Organization, Date Posted. URL.

Examples

4. U.S. Federal Civil Defense Administration, Duck and Cover (Archer Productions, 1951), from Internet Archive, Prelinger Archives, MPEG video, 9:15, http://archive.org/details/DuckandC1951.

5. "TNC:172 Kennedy-Nixon First Presidential Debate, 1960" YouTube video, 58:34, from televised debate September 26, 1960, posted by John F. Kennedy Library Foundation, September 21, 2010, http://www.youtube.com/watch?v=gbrcRKqLSRw.

"TNC:172 Kennedy-Nixon First Presidential Debate, 1960." YouTube video, 58:34. From televised debate September 26, 1960. Posted by John F. Kennedy Library Foundation, September 21, 2010. http://www.youtube.com/watch?v=gbrcRKqLSRw.

U.S. Federal Civil Defense Administration. Duck and Cover. Archer Productions, 1951. From Internet Archive, Prelinger Archives. MPEG video, 9:15. http://archive.org/details/DuckandC1951.


Television

For more information see: Chicago Style Q & A

Format

note:

6. TV Show Title, episode no. Number, first broadcast Date by Network, directed by Director First Name Last Name and written by Writer First Name Last Name.

bibliography:

TV Show Title. Episode no. Number, first broadcast Date by Network. Directed by Director First Name Last Name and written by Writer First Name Last Name.

Example

6. Jane the Virgin, episode no. 1-1, first broadcast October 13, 2014 by The CW, directed by Brad Silberling and written by Jennie Snyder Urman.

Jane the Virgin. Episode no. 1-1, first broadcast October 13, 2014 by The CW. Directed by Brad Silberling and written by Jennie Snyder Urman.


Image

For more information see: CMOS Shop Talk

Format

note:

7. Artist/Photographer First Name Last Name. Title of the Work, Year Created, Medium, Size, Institution Where Original Held, accessed Date Accessed, URL.

bibliography:

Images are not usually included in a bibliography.

If the image was accessed in a book or library database, replace access date and URL with book citation or database name. Use the information about the work provided in the source you used.

Examples

7. Edgar Degas, The Dance Class, 1874, oil on canvas, 32 7/8 x 30 3/8 in., Metropolitan Museum of Art, accessed May 15, 2015, http://www.metmuseum.org/art/collection/search/438817.

8. Hilaire-Germain-Edgar Degas, The Dance Class, probably 1874, oil on canvas, 32 3/4 x 30 1/4 in., Metropolitan Museum of Art, ArtStor.

9. Edgar Degas, The Dance Class, 1875-1876, oil on canvas, 33 x 31 3/4 in., Metropolitan Museum of Art, in Anne Dayez, Michel Hoog, and Charles S. Moffett, eds., Impressionism: A Centenary Exhibition, the Metropolitan Museum of Art, December 12, 1974-February 10, 1975 (New York: Metropolitan Museum of Art, 1974.), 105.

Examples: Government Documents

Congressional Hearing

For more information see: Chicago Manual of Style, 14.296

Format

note:

1. Chamber Committee Name, Hearing Title, Congress Number Cong., Session Number sess., Date of Hearing, Cited Page(s).

bibliography:

U.S. Congress. Chamber. Committee Name. Hearing Title. Congress Number Cong., Session Number sess., Date of Hearing.

If hearing was found online, include URL or database name at the end of the citation.

Example

1. U.S. Congress. House. Committee on International Relations. The Threat from International Organized Crime and Global Terrorism: Hearing before the Committee on International Relations. 105th Cong., 1st sess., October 1, 1997.

U.S. Congress. House. Committee on International Relations. The Threat from International Organized Crime and Global Terrorism: Hearing before the Committee on International Relations. 105th Cong., 1st sess., October 1, 1997.

Examples: Unpublished/Archival

Interview/Discussion

For more information see: Chicago Manual of Style, 14.219

Format

note:

1. Interviewee First Name Last Name (Brief Identifying Information), interview by First Name Last Name, Place, Date.

bibliography:

Interviews are usually cited in text or in notes only.

  • If you conducted the interview, indicate "by author" instead of using your name.
  • Published interviews are cited based on the source type in which they appeared. (CMOS, 14.221)
  • For discussions, replace "interview by" with "discussion with"
Example

1. Adam Falk (college president, Williams College), interview by author, Williamstown, MA, May 15, 2016.


Manuscript/Archival Material

For more information see: Chicago Manual of Style, 14.87

Format

note:

2. Item, Date, Collection Name, Repository Name, Place

bibliography:

Specific items are not included in the bibliography unless only one item from a collection is cited. The bibliographic entry gives details about the collection only.

Collection Name. Repository Name. Place.

If the item was accessed online, include the URL at the end of the citation.

Example

2. Mark Hopkins to Jaime Margalotti, 22 March 1861, Hopkins Family Papers, Williams College Special Collections, Williamstown, MA.

Hopkins Family Papers. Williams College Special Collections. Williamstown, MA.

 

Need More Info?

What Needs to be Cited?

  • Exact wording taken from any source, including freely available websites
  • Paraphrases of passages
  • Indebtedness to another person for an idea
  • Use of another student's work
  • Use of your own previous work

You do not need to cite common knowledge.