Bibliography  
    The following books provide additional information:  
    300 Leica Copies - Patrice-Herve Pont and Jean-Loup Princelle - FOTOSAGA, Neuilly, 1990  
    Canon Rangefinder Cameras 1933 - 68 - Peter Dechert - Hove Foto Books  
    Leica Copies - By HPR - Classic Collection Publications, 1994 (ISBN: 1-874485-05-4)  
    McKeowan's Price Guide To Antique And Classic Cameras (ISBN: 0-931838-28-2)  
    The Authentic Guide To Russian And Soviet Cameras - Jean-Loup Princelle - Hove Foto Books
(ISBN: 1-874031-63-0 (English) / 1-874031-02-9 (French))