Sutton, Jason R.; Stohlgren, Thomas J.; Beck, K. George (2007-01-17). "Predicting yellow toadflax infestations in the Flat Tops Wilderness of Colorado". Biological Invasions. 9 (7): 783–793. doi:10.1007/s10530-006-9075-8. ISSN1387-3547.
"Devils Causeway". www.rockymountainhikingtrails.com. Retrieved 16 Feb 2021.
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Sutton, Jason R.; Stohlgren, Thomas J.; Beck, K. George (2007-01-17). "Predicting yellow toadflax infestations in the Flat Tops Wilderness of Colorado". Biological Invasions. 9 (7): 783–793. doi:10.1007/s10530-006-9075-8. ISSN1387-3547.