00835cam a22002537a 4500003000500000005001700005008004100022010001000063011001000073020001500083035001000098040000900108082001600117100002200133245017300155260005300328300002300381410003700404650002500441650003400466700002200500700002200522810003700544CHAP20220329141851.0980317d1995    us      r     00110 eng d  a75014  a75986  a0801429374  a85560  cCHAP04a630.72bA5500aAlston, Julian M.10aScience under scarcity :bprinciples and practice for agricultural research evaluation and priority settingc/by Julian M. Alston, George W. Norton and Philip G. Pardey0 aIthaca, N.Y. :bCornell University Press,c1995.  a585 p. :bgráfs.21aFood systems and agrarian change14aAgriculturaxCostos.14aAgriculturaxInvestigación.0 aNorton, George W.0 aPardey, Philip G.00aFood systems and agrarian change