Place edition information after the title.
Express numbers representing editions in arabic ordinals, as first becomes 1st, IV becomes 4th.
Abbreviate the word "edition" and other descriptive words:
End with a period.
Schott J, Priest J. 2002. Leading antenatal classes: a practical guide. 2nd ed. Boston (MA): Books for Midwives.
Words expressing edition for electronic publications are not as widely known and are not abbreviated (188.8.131.52 and 184.108.40.206).
Version 2.0, Update 6.1
Sample end reference:
IMGT/HLA Sequence Database [Internet]. 2003. Release 2.9.0. Cambridge (England): European Bioinformatics Institute. [updated 2005 Jun 1; cited 2005 Jun 22]. Available from: http://www.ebi.ac.uk/imgt/hla/.
Journals and Newspapers
Editions for journal titles and newspapers are usually published simultaneously and are considered part of the title. Place the abbreviated edition (capitalized) in parenthesis following the title proper. End the complete title with a period.
Journal: BMJ (Int Ed.).
Newspaper: Washington Post (Final Ed.).