00327nam a2200121 a 450000500170000002000150001708200230003210000220005524500660007725000110014326000300015430000210018420251203092010.0 a0803959362 a361.61068,bD, moh aMohr, Lawrence B. aImpact analysis for program evaluation, Lawrence B. Mohr, eng a2nd ed aLoNew Delhion, Sagec1995 axxii,310p.c22cm