UNDERSTANDING HUMAN SEXUALITY FIFTH EDITION
JANET SHIBLEY HYDE1994 年出版769 页ISBN:0070316155
UNDERSTANDING ORGANIZATIONAL BEHAVIOR SECOND EDITION
STUART M.KLEIN1984 年出版692 页ISBN:0534031196
Understanding humic substances advanced methods
properties and applications1999 年出版286 页ISBN:0854047999
EARTH SCIENCE UNDERSTANDING ENVIRONMENTAL SYSTEMS
EDGAR W.SPENCER著2222 年出版518 页ISBN:0072341467