Calvert, W. H., W. Zuchowski, and L. P. Brower. “The Impact of Forest Thinning on Microclimate in Monarch Butterfly (Danaus Pexippus L.) Overwintering Areas of Mexico”. Botanical Sciences, no. 42, Aug. 1982, pp. 11 -8, doi:10.17129/botsci.1257.