You will need to collect some important information about the letter. This information will be used to craft your actual citation. According to the sixth edition (second printing) of the Publication Manual of the American Psychological Association, you need to determine the name of the letter's author, as well as the date the letter was published. Additionally, you will need to identify the number of the page on which the letter ran, the title of the letter and the name of the publication. Finally, you will need the volume and issue number of the publication.
Craft the Citation
Now, you can piece together your citation. Begin by listing the name of the author (last name first, followed by a comma and the first name) and a period. Next, place the date of publication in parentheses and end with another period. Then, list the title of the letter and immediately follow that with the phrase "letter to the editor" placed in square brackets; include another period. Next, list the title of the publication, a comma and the volume number, all in italics. Immediately following that, place the issues number in parentheses, a comma and the page number the letter was printed on. The citation will likely run longer than one full line. After the first line, each consecutive line should be indented one-half inch.