Constenla Umaña, M. A., Riley, D., Kennedy, S. H., Rojas Sánchez, C. E., Mora Alfaro, L. E., & Stevens, J. E. B. (1990). Paraquat Behavior in Costa Rican Soils and Residues in Coffee.

Constenla Umaña, Manuel Arturo, Dave Riley, Steve H. Kennedy, Carlos Enrique Rojas Sánchez, Luis Enrique Mora Alfaro, y John E. B. Stevens. Paraquat Behavior in Costa Rican Soils and Residues in Coffee. 1990.

Constenla Umaña, Manuel Arturo, et al. Paraquat Behavior in Costa Rican Soils and Residues in Coffee. 1990.