1. Cadahía D. 1983. Nuevos problemas fitosanitarios. Boletin del Servicio de Plagas 9:275–285.
2. Ceballos L, Ruíz de la Torre J. 1971. Árboles y Arbustos de la España Peninsular. IFIE-ETSI de Montes (Instituto Forestal de Investigaciones y Experiencias — Escuela Técnica de Ingenieros), Madrid.
3. Cobianchi D, Watkins R. 1984. Descriptor List for Plums and Allied Species. International Board for Plant Genetic Resources. Rome, Italy.
4. Diez CJ, Gil L. 1998a. Effects of Ophiostoma ulmi and Ophiostoma novo-ulmi culture filtrates on elm culture from genotypes with different susceptibility to Dutch Elm Disease. European Journal of Forest Pathology (in press).
5. Díez CJ, Gil L. 1998b. Variability in pheny lalanine ammonia-lyase activity among cell cultures of elm clones inoculated with Ophiostoma novo-ulmi spores. Plant Pathology (in press).