Cacti of the United States and Canada, Lyman Benson, 1983 ISBN-13: 978-0804708630 ISBN-10: 0804708630 Cacti of Texas A Field Guide with Emphasis on the Trans-Pecos Species A. Michael Powell, James F. Weedin, and Shirley A. Powell, 2008 ISBN978-0-896-72611-6 Cacti of Texas in their Natural Habitat, Ad Konings, 2009 ISBN-10: 1932892087 ISBN-13: 978-1932892086 Opuntia Web https://www.opuntiads.com/opuntia-lindheimeri/