- Definition of Descriptive Bibliography by Terry Belanger http://www.bibsocamer.org/bibdef.htm
- Williams, William Proctor and Craig S. Abbot. An Introduction to Bibliographical & Textual Studies. 4th Edition. (NY: The Modern Language Association of America, 2009) See Chapter 1 - Introduction
It's a difficult question to answer, particularly for one who looks at practice and not theory.
When we talk about editions and their various forms we are looking at an instance of setting type and looking at how that set type varies over time until the type is reset (new edition). One of the issues with FRBR and RDA for Rare Books is the loss of the granularity between editions, impressions, and issues. If they are all lumped together, it will become impossible to actually identify different editions, impressions, and issues, not to mention comments about state (minute changes in layout, punctuation, and errors in pagination).
Rare Book librarians have been revising and updating their cataloging procedures and protocols in light of FRBR and RDA, http://rbms.info/dcrm/ but it is a slow process and they aren't ready to jettison the specificity of AACRII 2nd edition in favor of something that doesn't take that specificity into account.
As the semester progresses, we'll look at many reference tools and articles that will help us understand how to differentiate and describe editions. That's what analytic or descriptive bibliography is all about. Take a look at the diagram in Belanger and the discussion in Williams to get a better understanding of definitions for bibliography. Both contain visual examples of bibliographies.