Two citation systems in one: Notes-Bibliography for history and humanities dissertations, Author-Date for social science and business dissertations. Full examples for every source type, plus formatting rules and a side-by-side comparison.
Chicago style is published by the University of Chicago Press and is now in its 17th edition. It is one of the most comprehensive and widely used citation styles in academia. Unlike APA or IEEE, Chicago offers two completely different citation systems within the same manual — you choose the one appropriate for your discipline or as specified by your instructor.
The two systems are:
Both systems produce the same information — the difference is where and how the citation information appears in the dissertation. Before you write a single word of your literature review, confirm with your committee chair which system your program requires.
| Discipline | Recommended System |
|---|---|
| History, Philosophy, Literature, Arts, Religion | Notes-Bibliography (NB) |
| Business and Management | Author-Date (AD) |
| Social Sciences (Sociology, Political Science) | Author-Date (AD) |
| Economics | Author-Date (AD) |
| Anthropology | Author-Date (AD) |
| Interdisciplinary / Committee's choice | Confirm with your chair |
In the NB system, citations appear as superscript numbers in the text — ¹ ² ³ — corresponding to footnotes at the bottom of each page (or endnotes at the end of the paper). A Bibliography containing all sources appears at the end.
Key difference between footnotes and bibliography entries: footnotes list the author in normal order (First Last); bibliography entries invert the first author (Last, First) for alphabetical sorting. Footnotes end with the page number cited; bibliography entries end with the full page range.
Ibid.: In Chicago NB, when you cite the exact same source consecutively in two footnotes, you may write "Ibid." for the second note (followed by a page number if different). Many committees now discourage ibid. in favour of shortened notes — confirm before using it.
Notes-Bibliography or Author-Date — our specialists handle both systems with full source coverage.
The Author-Date system uses parenthetical in-text citations — (Author Year, page) — rather than footnotes. A Reference List appears at the end of the paper, sorted alphabetically. This system is functionally similar to APA but with important differences in punctuation and format.
| Scenario | Format | Example |
|---|---|---|
| One author | (Last Year) | (Smith 2022) |
| Two authors | (Last and Last Year) | (Smith and Jones 2022) |
| Three or more | (Last et al. Year) | (Smith et al. 2022) |
| With page number | (Last Year, page) | (Smith 2022, 45) |
| Two works, same citation | (Last Year; Last Year) | (Smith 2022; Jones 2023) |
Chicago AD vs APA: Chicago author-date does NOT put a comma between the author and year: (Smith 2022) not (Smith, 2022). This is one of the most consistent points of confusion when switching between the two styles.
| Feature | Notes-Bibliography (NB) | Author-Date (AD) |
|---|---|---|
| In-text marker | Superscript footnote number ¹ | Parenthetical (Last Year) |
| End-of-paper list | Bibliography (alphabetical) | Reference List (alphabetical) |
| First author in list | Inverted: Last, First | Inverted: Last, First |
| Year position | After publisher: Press, 2016. | After author: 2016. Title… |
| Comma between author & year (in-text) | N/A (footnote) | No comma: (Smith 2022) |
| Article title | "Quoted" | "Quoted" (same) |
| Book/journal title | Italicised | Italicised (same) |
| Publisher location | Required: (City: Publisher) | Required: City: Publisher |
Both are acceptable in the NB system — check your instructor's preference. Footnotes are more conventional for published work; endnotes are sometimes easier to manage in long student papers. The formatting of the note itself is identical either way.
Use "Ibid." when you cite the exact same source in two consecutive footnotes with no other source in between. "Ibid., 150" means the same work as the previous footnote but page 150. Many committees now prefer shortened notes instead — use the author's last name and a short title: Said, Orientalism, 150.
Kate Turabian's A Manual for Writers is essentially a student-adapted version of Chicago, written specifically for theses and dissertations. The two systems follow the same citation formats. Turabian adds guidance specific to graduate research papers (title pages, formatting requirements). See our Turabian guide for the dissertation-specific details.
Use the organisation's name, title of the work, or a shortened title in place of the author. In-text: (American Nurses Association 2023) or (Condition of Education Report 2023). In the reference list, file it alphabetically by the first significant word.
It depends on your discipline. Use Author-Date if you're in business, social science, or some education programs — it functions like APA and Harvard. Use Notes-Bibliography if you're in history, philosophy, or the humanities. Check your program handbook or ask your committee chair before drafting your reference list.