The Chicago Manual of Style sets out two approaches to referencing sources in academic writing, one of which uses parenthetical citations. And while the basic in-text citation format is easy to grasp, it varies in many situations.\n\nIn this post, then, we\u2019re looking at how to make sure your referencing is always error free when using Chicago author\u2013date citations.\n1. Basic Chicago Author\u2013Date Citations\nChicago author\u2013date citations require giving the surname of the author and the year of publication for a source in round brackets. This is usually at the end of the relevant clause. For example:\nThere are many approaches to referencing (Fry 2001).\nIf the author is already named in the text, you do not need to repeat it in the citation. Instead, simply cite the year of publication immediately after the author is named:\nFry (2001) says that there are many approaches to referencing.\n\n2. Citing a Work with Two or More Authors\nTo reference a source with two authors using Chicago author\u2013date citations, simply give both names in the order they are listed on the book, joined with the word \u201cand\u201d (not \u201c&\u201d):\nTwo is the best number (Fry and Smith 1998).\nFor a source with three authors, use a serial comma before the last name:\nThree is still a good number (Fry, Smith, and Connor 2011).\nIf a source has four or more authors, cite the first name followed by \u201cet al.\u201d:\nIt turns out that four is too many (Fry et al. 2017).\nYou should, however, name all of the authors in the reference list at the end of your document.\n3. Quoting Sources\nTo quote a source with Chicago referencing, give the page number(s) in the citation after a comma:\nHe said it \u201cexactly like this\u201d (Smith 1984, 23).\nFry (2001, 12-13) argues that \u201ceyewitness accounts are unreliable.\u201d\nThe first citation above shows us that the quote comes from page 23 of the source in question. The second shows us that the quote comes from pages 12-13 of the source cited.\n4. Two Works by the Same Author from the Same Year\nIf you cite two sources written by the same author in the same year, a year of publication alone won\u2019t be enough to show which source you\u2019re citing.\n\nIn this situation, you should also add a letter after the year for each source that you cite in your work. For example, in the reference list, sources by the same author should be ordered alphabetically by title. If they are also from the same year, you will add \u201ca\u201d after the first, \u201cb\u201d after the second, etc.\nFry, John. 1990a. D\u00e9j\u00e0 Vu and You. New York: Simon & Schuster.\n\u2014\u2014\u2014. 1990b. False Recollections. New York: Penguin Press.\nTo show which source is which in citations, simply include the correct letter:\nFry (1990a) originally worked on d\u00e9j\u00e0 vu. But he later examined the sense of having already lived through a present moment (Fry 1990b).\nIn the passage above, for instance, we cite two sources by \u201cFry\u201d from the year 1990. We have therefore added the letters \u201ca\u201d and \u201cb\u201d to show that they are distinct texts.\n5. Two Authors with the Same Surname\nTo cite two authors with the same name, include first initials in citations:\nThe Earth revolves around the Sun (J. Smith 2004). However, people once believed that the Sun revolved around the Earth (R. Smith 1992).\nYou should list the authors with first names in full in the reference list, however, just like you would with any other author.\n6. Citing More than One Source at Once\nYou can also cite more than one source in a single citation. To cite two or more sources by a single author at once, for example, you can simply add a comma between the years of publication:\nStudies have shown that the Earth is round (Smith 1971, 1982, 2006).\nHere, for instance, we\u2019ve cited three sources by \u201cSmith\u201d all at once. You can also cite more two or more sources by different authors. To do this, use a semicolon between each author\u2019s surname:\nSome people still believe in a flat Earth (Fry 2015; Smith 2006).\nNames in a citation can be ordered alphabetically, chronologically, or by importance. It is simply a matter of clarity and preference. Here, we\u2019ve ordered them alphabetically.