J. A. SilvaDepartment of Agronomy and soils science College of Tropical Agriculture University of Hawaii and Depertment of Agronomy and soils college of Agricultural sciences University of Puerto Rico[1978]
F.H.BeinrothDepartment of Agronomy and Soils College of Agricultural Sciences University of puerto Rico and Department of Agronomy and Soils science College of Tropical Agriculture and Human Resources University of Hawaii[1979]