00417nam a2200145 a 450000100080000000500110000800800410001910000190006024500820007926000350016130000100019665300290020670000160023570000200025110517742007-03-12       2002    bl uuuu      00u1 u    #d1 aSHADISH, W. R.  aExperimental and quasi-experimental designs for generalized causal inference.  aBoston: Houghton Mifflinc2002  a623p.  aEstatistica experimental1 aCOOK, T. D.1 aCAMPBELL, D. T.