Talk:Strategic planning software

Should always the newest book be referenced?
In References this is listed: Kenneth S. Rubin (20 July 2012). Essential Scrum: A Practical Guide to the Most Popular Agile Process. Addison-Wesley. pp. 34–. ISBN 978-0-321-70037-7. I am reading the 2013 edition of Essential Scrum: A Practical Guide to the Most Popular Agile Process. Addison-Wesley. pp. 34–. The ISBNs for this book are: ISBN-13: 978-0-13-704329-3 ISBN-10:    0-13-704329-5