00577cam a22001937a 4500003000500000005001700005008004100022010001000063011001000073035001000083040000900093100002200102245010200124500005400226650002700280650002700307700002500334700002400359CHAP20220329141346.0971013s                r     00010     d  a67004  a67976  a77448  cCHAP00aAnderson, Jack R. 0aVariability of cereal yields; sources of change and implications for agricultural research policy  aSobretiro de : Food Policy 12 (3) : 199-212, 198714aCerealesxRendimiento.14aPolítica agrícola.0 aEvans, Lloyd Thomas.0 aHacell, Peter B. R.