Established patient visits all require 2 out of 3 of history, exam, medical decision making

99212:
History required is problem focused: 1-3 HPI elements

Exam required is problem focused: 1 body area/organ system examined from the 1995 exam, or one bullet from the multi-specialty exam or any single specialty exam from 1997

Straightforward MDM (one resolved problem, one minor problem)

See the articles on auditing and the Documentation Guidelines in Codapedia. 

There are sample, audited notes attached in the resources page of this article.