Zúñiga B., Malda G., Suzán H., Interacciones Planta-Nodriza en Lophophora diffusa (Cactaceae) en un Desierto Subtropical de México, Biotropica, 2005, 37(3):351-356, doi: 10.1111/j.1744-7429.2005.00046.x
A SADIE analysis of the distribution of Lophophora diffusa and neighbouring shrubs, combined with assessment of light, temperature and humidity beneath their canopies. The abstract indicates a positive association with Larrea tridentata and a negative association with Celtis pallida. The authors consider limited seedling development in the deepest shade. The publisher's abstract was available.