Reference List Citations
The basic APA reference list format for a book is as follows: Author's Last Name, First Initial(s). (Year of Publication). Title of book: Subtitle. Publication location: Publisher name.
A citation for a source with a missing date should include a note that the date is not available. Replace the year of publication with "n.d." This is true for all types of reference list citations in APA style, including websites, periodicals and multimedia documents.
For example: Bern, J. (n.d.). My time in the Andes. Topeka, KA: Prairie Publishers.
Dates are also required in in-text citations; with these, the author's name, publication year and page number of cited information are placed in parentheses. Noting a source with no date is a simple substitution. Put "n.d." in place of the year.
For example: (Bern, n.d., p. 18)