Echinocereus engelmannii subsp. engelmannii
- 1. Sánchez, D. 2021: Revision of Echinocereus – In: Korotkova N. & al., Cactaceae at Caryophyllales.org – a dynamic online species-level taxonomic backbone for the family. – Willdenowia 51(2): 250-270. http://doi.org/10.3372/wi.51.51208