Ronnie 1995, p. 37. Ronnie, Art (1995). Counterfeit hero : Fritz Duquesne, adventurer and spy. Annapolis, Md.: Naval Institute Press. ISBN1-55750-733-3. OCLC605599179.
Ronnie 1995, pp. 54, 63. Ronnie, Art (1995). Counterfeit hero : Fritz Duquesne, adventurer and spy. Annapolis, Md.: Naval Institute Press. ISBN1-55750-733-3. OCLC605599179.
Ronnie 1995, pp. 65–66. Ronnie, Art (1995). Counterfeit hero : Fritz Duquesne, adventurer and spy. Annapolis, Md.: Naval Institute Press. ISBN1-55750-733-3. OCLC605599179.