From the category archives:

Four

Diagnostic Dream: Malfunctioning Red Four-Cylinder Engine

by Stephen Parker, Ph.D. (Article Selection, Commentary) on June 28, 2010

Diagnostic Dream: Atrial Fibrillation

by Stephen Parker, Ph.D. (Article Selection, Commentary) on June 28, 2010

Diagnostic Dream: Four Black Horses

by Stephen Parker, Ph.D. (Article Selection, Commentary) on June 6, 2010