APA Format
Cullis, Harry, (n.d.) Clarkson Guyer for Colorado Reflections. Retrieved from Special Collections @ DU, https://specialcollections.du.edu/object/b989f433-c9b3-4242-b3b0-54c984e4903b
MLA Format
Cullis, Harry. (n.d.) Clarkson Guyer for Colorado Reflections. Retrieved from Special Collections @ DU <https://specialcollections.du.edu/object/b989f433-c9b3-4242-b3b0-54c984e4903b>.
Chicago Format
Cullis, Harry. Clarkson Guyer for Colorado Reflections. n.d.. Retrieved from Special Collections @ DU, https://specialcollections.du.edu/object/b989f433-c9b3-4242-b3b0-54c984e4903b. (Accessed February 27, 2025.)