TY  - BOOK
AU  - Koba, Susan
AU  - Tweed, Anne
TI  - Hard-to-teach biology concepts : : a framework to deepen student understanding 
SN  - 978-1-933531-41-0
AV  - 570.712 K79h 
PY  - 2009///
CY  - Arlington, Va.
PB  - NSTA Press
KW  - Biology
KW  - Study and teaching (Secondary)
N1  - Includes bibliographic references and index
ER  -