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6. Posnette, Rep. W. Afr. Cocoa Res. Inst. 1947-48: 11, 1948.
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8. Thresh, Rep. W. Afr. Cocoa Res. Inst. 1956-57: 72, 1958.
9. Thresh & Tinsley, Tech. Bull. W. Afr. Cocoa Res. Inst. 7: 8 pp., 1959.