00271nam a2200109 a 450000500170000002000170001708200210003410000180005524500430007326000300011630000150014620251203090450.0  a008039220571  a300.722,bD, Yin  aYin, Robert K  aCase study research:Design and methods  aLoNew DelhionbSagec1986  a160p, 22cm