Rodríguez-Ruiz, A. M., N. Chaves-Barrantes, A. Hernández-Díaz, and F. Herrera-Murillo. “Assessment of Poa Annua Resistance to Clethodim in Costa Rica”. Agronomía Mesoamericana, vol. 26, no. 2, June 2015, pp. 257-66, doi:10.15517/am.v26i2.19325.