Obvious Adams
Robert R. Updegraff & Dr. Robert C. Worstell
Robert Collier Copywriting Course
Dr. Robert C. Worstell & Robert Collier
How to Write a Good Ad
Dr. Robert C. Worstell & Victor O. Schwab
My Life in Advertising
Dr. Robert C. Worstell & Claude C. Hopkins
How to Sell Without Selling
Dr. Robert C. Worstell, Orison Swett Marden & Edward Berman
Breezy
Dr. Robert C. Worstell & J. George Frederick
Scientific Advertising
Dr. Robert C. Worstell & Claude C. Hopkins
The What, How, and Why of Advertising
Dr. Robert C. Worstell & John E. Kennedy
The Untold Story of Advertising
Dr. Robert C. Worstell