1. Stable Isotopes Research Group and Water Resources Management Laboratory, School of Chemistry, Universidad Nacional, Heredia, Costa Rica
2. Department of Geography and Water and Global Change Observatory, University of Costa Rica, San José, Costa Rica
3. International Atomic Energy Agency, Isotope Hydrology Section, Vienna International Center, Vienna, Austria
4. Empresa de Servicios Públicos de Heredia (ESPH), Heredia, Costa Rica