TY  - BOOK
AU  - Cook,Thomas D.
AU  - Campbell, Donald Thomas, 1916-
TI  - Quasi - experimentation: design & analysis issues for field settings 
SN  - 0-395-30790-2
U1  - 300.7 2 
PY  - 1979///
CY  - Boston, Mass.
PB  - Houghton Mifflin
KW  - Ciencias Sociales
KW  - Investigación
ER  -