According to the seventh edition of the APA manual, when available, you should include the DOI (digital object identifier) in the form of a URL (starting with https://...) for print and electronic sources in the reference entry. The DOI number is placed at the end of the entry without ending punctuation:
Author, A. A., & Author, B. B. (Date of publication). Title of article. Title of Journal, volume(issue). https://doi.org/xxxxx
Publication Manual of the American Psychological Association
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If the book does not have a DOI and is an ebook from an academic research database, end the book reference after the publisher name. Do not include database information in the reference. Include a URL for ebooks from other websites. Do not put a period after the DOI or URL.
If the document is composed of multiple web pages, give the URL of the home page or entry page for the document. If no publication or "last modified" date is apparent, use n.d. in place of the publication date. Retrieval dates: include only if the work is unarchived and designed to change over time. Most references do not include retrieval dates.
Give chapter or section numbers (if available) in place of page numbers. Provide the URL that points to the first page of the chapter or section you are citing. Retrieval dates: include only if the work is unarchived and designed to change over time. Most references do not include retrieval dates.
Provide the URL of the newspaper home page when the online version of the article is available by search to avoid nonworking URLs.
If the online version refers to an existing print edition, include the edition number of the print version after the title. Retrieval dates: include only if the work is unarchived and designed to change over time. Most references do not include retrieval dates.
For a motion picture, the first executive producer and the first director should be listed as the responsible parties. If one of these parties fulfilled multiple creative roles in the film, all such roles should be listed. If credits for director and producer are not available, provide the name of the individual or organization most responsible for the work.
Do not italicize the names of software, programs, or languages. Include the version number (if any) in parentheses immediately after the title. Also, provide the location and name of the organization that produced the work (if applicable).
NOTE: For the following three entries, Provide the author's full name (if available) in the form of last name followed by first initials. If only a screen name is available, provide the screen name in place of the author. Include the exact date of the posting followed by the subject line of the message or "thread." Also, if available, provide the name of the list to which the message was posted if this information is not already included in the URL.
