Kossoff, Peter, Francisco Hernández, Marieta Visconti Vekoh-Pardo, and Michael Zimmerman. “Urban Helminthiasis in Two Socioeconomically Distinct Costa Rican Communities”. Revista de Biología Tropical 37, no. 2 (November 1, 1989): 181–186. Accessed June 26, 2025. https://archivo.revistas.ucr.ac.cr/index.php/rbt/article/view/23571.