TEACHER'S GUIDE TO ACCOMPANY UNDERSTANDING ECONOMICS
DR.ALLEN W.SMITH1986 年出版154 页ISBN:0676398960
METAPHYSICAL GROUNDING UNDERSTANDING THE STRUCTURE OF REALITY
FABRICE CORREIA BENJAMIN SCHNIEDER2012 年出版311 页ISBN:1107022898
OPENING DOORS:UNDERSTANDING COLLEGE READING SECOND EDITION
JOE CORTINA JANET ELDER1998 年出版598 页ISBN:0070244707