00499naa a2200169 a 450000100080000000500110000800800410001910000190006024501010007926000090018065000120018965000130020165300200021470000170023470000200025177300580027116102651995-06-27       1989    bl uuuu     u00u1 u    #d1 aHELLUMS, D. T.  aPotential agronomic value of calcium in some phosphate rocks from South America and West Africa.  c1989  aCálcio  aFósforo  aFosfato natural1 aCHIEN, S. H.1 aTOUCHTON, J. T.  tSoil Sci. Soc. Am. J.gv. 53, n. 2, p. 459-462, 1989.