"DC naturally" : a guide to Metropolitan Washington's environmental education resources / compiled by the: DC Environmental Education Consortium ; in cooperation with: Friends of the Earth and the U.S. Fish and Wildlife Service, Chesapeake Bay Field Office
100 [One hundred] teaching activities in environmental education / selected and edited by John H. Wheatley and Herbert L. Coon ; supervised by Robert E. Roth
A guide to the birds of Nicaragua = Una guía de aves / Juan Carlos Martinez-Sánchez, Liliana Chavarría-Duriaux, Francisco José Muñoz ; illustrations by Augusto Silva Gómez, et al