Authors: Delva, J Van Etten, ML Gonzalez, GB Cedeno, MA Penna, M Caris, LH Anthony, JC

Citation: J. Delva et al., First opportunities to try drugs and the transition to first drug use: Evidence from a national school survey in Panama, SUBST USE M, 34(10), 1999, pp. 1451-1467

Authors: Penna, M Solis, R

Citation: M. Penna et R. Solis, Extent and variation of sound enhancement inside burrows of the frog Eupsophus emiliopugini (Leptodactylidae), BEHAV ECO S, 47(1-2), 1999, pp. 94-103