By García-Molinari, Ovídio.
Río Piedras, Puerto Rico Agricultural Experiment Station, University of Puerto Rico 1952 .
l67 p. , "A thesis presented to the Faculty of the Graduate School, University of Nebraska, in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Botany." 23 cm..

By Más, Edwin G..
Mayagüez, P. R. Universidad de Puerto Rico, Recinto Universitario de Mayagüez, Colegio de Ciencias Agrícolas, Servicio de Extensión Agrícola 1990 .
iii, 103 p.