Díaz-Ferguson, E. and Vargas-Zamora, J.A. 2001. Abundance of <i>Petrolisthes armatus</i> (Crustacea: Porcellanidae) on a tropical estuarine intertidal rocky beach, Gulf of Nicoya estuary, Costa Rica. Revista de Biología Tropical. 49, S2 (Dec. 2001), 97–101.