1. Identification of tulip cultivars based on polymorphism in esterase isozymes from bulb scales;Booy;Euphytica,1993
2. Tulips. Taxonomy, morphology, cytology, phytogeography and physiology;Botschantzeva,1982
3. The genus Tulipa;Hall,1940
4. On the origin of Tulipa;Hoog,1973
5. Het raadsel van de Neo-Tulipae;Hoog,1974