References
- Cole , C.V. , Grunes , D.L. , Porter , L.K. and Olsen , S.R. 1963 . Soil Sci. Soc. Amer. Proc. , 27 : 671 – 674 .
- Gooding , E.G.B. 1971 . Expt. Agric. , 7 : 315 – 319 .
- Irving , H. 1956 . Trop. Agric. (Trinidad) , 33 : 67 – 78 .
- Litzenberger , S.C. , ed. 1974 . “ Yams ” . In Guide for Field Crops in the Subtropics , 236 Washington, D.C. : Office of Agriculture, Technical Assistance Bureau, Agency for International Development . Ch. 29,
- Lott , W.L. , Nery , J.P. , Gallo , J.R. and Medcalf , J.C. 1956 . Leaf analysis technique in coffee research , 26 New York, , U.S.A. : IBEC Research Institute .
- Martin , F.W. 1974 . Tropical yams and their potential. Part 2. Dioscorea bulbifera , 20 Agricultural Research Service, USDA/AID . Agricultural Handbook No. 466
- Sobulo , R.A. 1972a . Expl. Agric. , 8 : 99 – 106 .
- Sobulo , R.A. 1972b . Expl. Agric. , 8 : 107 – 115 .
- Wood , R.C. 1933 . Expl. Agric. , 1 : 316 – 324 .