Heavy Duty (G.I. Joe) - Wikipedia

Heavy Duty (Movie), Joepedia

Heavy Duty (v6) G.I. Joe Action Figure - YoJoe Archive

Hawk (G.I. Joe) - Wikipedia

G.I. Joe: A Real American Hero (1989 TV series) - Wikipedia

Critical Point of View: A Wikipedia Reader by Institute of Network

Beach Head (G.I. Joe), Neo Encyclopedia Wiki

Cobra Commander - Wikipedia

Heavy Duty (G.I. Joe) - Wikipedia

Thrasher (G.I. Joe), Neo Encyclopedia Wiki

Heavy Duty (v1) G.I. Joe Action Figure - YoJoe Archive

GI Joe (2001 Image/Devil's Due) comic books

Stalker (G.I. Joe), Neo Encyclopedia Wiki