R. Gordón-M., J. Franco, N. De Gracia, and A. González, “CORN RESPONSE TO DIFERENT LEVELS OF NITROGEN IN ROTATION WITH MUCUNA UNDER TWO TYPES OF TILLAGE. RIO HATO, PANAMA. 1993-1994.”, ciencia-agropecuaria, no. 12, pp. 55-70, Sep. 2002.