In 1927, Spalding's Official Pacific Coast Interscholastic Foot Ball Guide reported that "Charles Dvorak, the renowned player of former years on Yost's University of Michigan team," was coach at Roosevelt High School.
In 1927, Spalding's Official Pacific Coast Interscholastic Football Guide stated that Charles Dvorak, a notable player from the University of Michigan under Coach Yost, was coaching at Roosevelt High School.