1. Butterflies of the Colorado Front Range:  A Photographic Guide to 100 Species, 2^nd Edition, Janet R. Chu and Stephen R. Jones (2020)
2. Butterflies of the Colorado Front Range:  A Photographic Guide to 80 Species, Janet R. Chu and Stephen R. Jones (2011)
3. Butterflies of the Rocky Mountains:  Idaho, Montana, Wyoming, Utah, Colorado, Northeastern Arizona & Northern New Mexico, A Guide to Common and Notable Species [Pamphlet], Roland H. Wauer (2012).   A waterproof, foldable quick guide.
4. Butterflies of Rocky Mountain National Park, Leslie Angel (2005)
5. Caterpillars in the Field and Garden, Thomas Allen, Jim Brock and Jeffrey Glassberg (2005)
6. Butterflies of North America, Jim P. Brock and Kenn Kaufman (2003)
7. Butterflies through Binoculars: The West, Jeffrey Glassberg (2001)
8. A Field Guide to Western Butterflies, Paul Opler (1999)
9. Peterson First Guide to Butterflies and Moths, Paul Opler (1994)
10. Handbook for Butterfly Watchers, Robert Michael Pyle (1984)-(1992)
11. The Audubon Society Field Guide to North American Butterflies, Robert Michael Pyle (1981)

Websites

• • Butterflies and Moths of North America
  • Butterflies of America
  • Rocky Mountain National Park Butterfly Species List
  • Best Butterfly Trails in Boulder
  • iNaturalist - Butterflies and Moths
  • iNaturalist - Report a Sighting
  • Attracting Butterflies with Colorado Native Plants
  • North American Butterfly Association - Butterfly Gardens
  • Xerces Society for Invertebrate Conservation