18. Rivers of Costa Rica - Catherine M. Pringle, Elizabeth P. Anderson, Marcelo Ardón, Rebecca J. Bixby, Scott Connelly, John H. Duff, Alan P. Jackman, Pia Paaby, Alonso Ramírez, Gaston E. Small, Marcia N. Snyder, Carissa N. Ganong, and Frank J. Triska