- Author: Robert B. Ekelund Jr., Robert D. Tollison
- Language: English
- Year: 2011
- Author: Robert B. Ekelund Jr
- Language: English
- Year: 1997
- Author: Robert B. Ekelund Jr., Mark Thornton
- Language: English
- Year: 2004
- Author: Robert B. Ekelund
- Language: English
- Year: 2014
- Author: Robert B. Ekelund, Robert F. Hébert
- Language: Spanish
- Year: 2005
- Author: Tollison Robert D., Ekelund Robert Burton
- Language: English
- Year: 2011
- Author: Robert Burton. Ekelund Jr. John D. Jackson Robert D. Tollison
- Language: English
- Year: 2017
- Author: Robert B. Ekelund Jr. Robert D. Tollison
- Language: English
- Year: 2011
- Author: Robert B Ekelund, Robert D Tollison, Gary M Anderson, Robert F Hebert, Audrey B Davidson
- Language: English
- Year: 1996