00281nam a22000977a 4500040000700000082000800007100001600015245012300031260002000154300000900174  cSY  a610  aS.N.H. PUTT  aveterinary epidemiology and economics in africa- manual for use in the desihn and appraisal of livestock health policy  aRUAbPUTTc1988  a94p.