"The American Society of Agronomy (ASA), Crop Science Society of America (CSSA), and Soil Science Society of America (SSSA) Publications Handbook and Style Manual serves as a guide for authors in preparing manuscripts and other material submitted for publication by ASA, CSSA, and SSSA." Refer to Chapter 1, Pages 10-19 for citation guidelines and examples.
"ASA, CSSA, SSSA journals follow the APA style for citations and references. The author-year system for citations is required; do not use numbered references. Refer to chapter 1 of the Publications Handbook and Style Manual for examples of our reference and citation style, in addition to following these guidelines:
Arrange the list alphabetically by the surnames of the first authors and then by the second and third authors.
Single-authored articles should precede multiple-authored articles for which the individual is first author.
Two or more articles by the same author are listed chronologically; two or more in the same year are indicated by a, b, c, etc.
Only literature that is available through libraries or other readily accessible public media can be cited. Material that does not meet this standard should be cited as personal communication or unpublished data."