00284nam a22000977a 4500040000700000082000800007100001500015245012400030260002300154300000900177  cSK  a636  aPUTT S.N.H  aVeterinary epidemiology and economies in africa a manual for use in the design and appraisal of livestock health policy  aENGLANDbPUTc1987  a94p.