In the text of your paper, references in APA style are cited with an author-date method of citation (as compared to author-page number method in MLA style). The full description of the source can be found listed alphabetically in the Reference list at the end of the paper. Each reference cited in the text must appear on the reference list and each entry on the reference list must be cited in the text of the paper. If you are referring to an idea from another work but NOT direct quoting the work, or if you are making a reference to an entire article, book, or other work, you will only cite the author and date, and not the page number. If you are directly quoting from the work, then you will also need to include the exact page number where the information came from in your in-text citation.
Short Quotation: When directly quoting from a work, include the author, year of publication and the page number in the in-text citation. In APA style, you do include the "p." in the citation. Introduce the quote with a signal phrase that includes the author's last name followed by the date of publication in parentheses and put the page number at the end of the quotation. The citation is part of the sentence and the punctuation will come after the citation. Example:
If the author's name isn't included in the signal phrase, then place the author's name, year of publication, and page number in parentheses directly after the quotation:
Long Quotations: For quotations 40 words or longer, you should block quote them, omit the quotation marks, and place the parenthetical citation after the closing punctuation mark. Start the quotation on a new line, and indent the whole quotation 1/2 inch from the margin (tab in once). Keep the double spacing. For example:
Chandler (2005) explains:
Sometimes it is important to match a dog's personality with the population it is to work with. Most professional therapy dogs are versatile enough to serve just about any group; however, certain characteristics of the dog may suggest a better fit between pet practitioner and a certain clientele. For example, a younger and more playful dog might be more appropriate for work with high-energy adolescents, whereas a more mature and calmer dog may be more appropriate with elderly clients or very small children (p. 28).
Summary or Paraphrase: If you're paraphrasing or summarizing from a work, you only need the author and the year of publication; however, APA guidelines encourage providing the page number as well (though this is not required). For example:
According to Smith, 2010, owning a pet can decrease blood pressure and fatty acid levels in the blood (p. 14).
APA has important rules to follow on using author names as part of the author-date system. It also has rules for citing indirect sources, electronic sources and sources without page numbers.
A Work by Two Authors: You should name both authors in the signal phrase or in the parentheses each time you cite their work.
A Work by Three to Five Authors: List all of the authors in the signal phrase or in the parentheses the first time you cite the work, and in subsequent citations, use the first author followed by "et al."
Unknown Author: For a work with no author, use the title in the signal phrase, or in the parentheses, use the first word or two of the title.
Organization as Author: When the author of a source is an organization or government agency, mention the organization in the signal phrase or in the parenthetical citation the first time you cite the source.
Two or More Works in the Same Parentheses: For two or more works by different authors who are cited within the same parentheses, list them in the same order as they appear on the reference list and separate them with a semicolon.
Authors with the Same Last Name: Use the first initials with the last names to avoid confusion.
Two or More Works by the Same Author in the Same Year: When you have two sources by the same author published in the same year, use lower-case letters (a, b, c) with the year to order the entries in the reference list. Use the lower-case letters with the year in the in-text citation.
Introductions, Prefaces, Forewords, and Afterwords: If you are citing an Introduction, Foreword, or Afterword, cite the author and year as usual:
Personal Communication: When you are citing interviews, letters, emails, and other personal communication, cite the person's name, the fact that it was a personal communication and the date of the communication in the text of your paper. You will NOT include personal communication in the reference list.
So, how do you cite a source that was cited in another source? In this case, you'll want to name the original source in your signal phrase, but, in the parentheses, cite the source where you actually found the information and put that source information on your reference list. If possible, try to locate the original source so you can quote or paraphrase directly from that source, particularly if the information is important to a point you are trying to make.
Electronic Sources: If it's possible, you should cite electronic documents in the same way any other document is cited with the author-date style.
Unknown Author and Unknown Date: If there's no author or date given, then use the title in your signal phrase or the first word or two of the title in the parentheses and use the abbreviation "n.d." (for "no date").
Sources Without Page Numbers: In the case of an electronic source that doesn't have page numbers, you should try to include information that will help your reader locate the information you're citing. If the document has numbered paragraphs, then use the abbreviation "para." followed by the paragraph number.
Note: don't use the page numbers you see in your printed out version of a web article or in the pages listed by Adobe in a .pdf file. Different computers and printers will print out articles and page numbers differently.
APA does not recommend the use of footnotes and endnotes because they are often expensive for publishers to reproduce. However, if you find that you need explanatory notes, APA does allow for two types of footnotes - content and copyright. For a good explanation on how to format footnotes or endnotes, visit the Footnotes and Appendices page on the Purdue OWL's APA Formatting and Style Guide website.