Gutiérrez Marín, N., and A. López Soto. “Space Maintainers Placed from 2008 to 2011 at the School of Dentistry, University of Costa Rica”. Odovtos - International Journal of Dental Sciences, no. 15, Mar. 2014, pp. 13-19, https://revistas.ucr.ac.cr/index.php/Odontos/article/view/13729.