Horn, S. P., & Rodgers, J. C. (1996). The northern limit of Alnus (Fagales) in Costa Rica: Modern pollen evidence of a possible range extension.

Horn, Sally P., و John C. Rodgers. The Northern Limit of Alnus (Fagales) in Costa Rica: Modern Pollen Evidence of a Possible Range Extension. 1996.

Horn, Sally P., و John C. Rodgers. The Northern Limit of Alnus (Fagales) in Costa Rica: Modern Pollen Evidence of a Possible Range Extension. 1996.