The breed is believed to have been created from several different breeds of dogs that had the characteristics that Dobermann was looking for. The exact ratios of mixing, and even the exact breeds that were used, remain uncertain, although many experts believe that the Dobermann Pinscher is a combination of several breeds including the Beauceron, German Pinscher, Rottweiler and Weimaraner. The single exception is the documented crossing with the Greyhound and Manchester Terrier. It is also widely believed that the old German Shepherd was the single largest contributor to the Dobermann breed. Philip Greunig's "The Dobermann Pinscher" (1939) describes the breed's early development by Otto Goeller, who helped to establish the breed. The American Kennel Club believes the breeds utilized to develop the Dobermann Pinscher may have included the old shorthaired shepherd, Rottweiler, Black and Tan Terrier and the German Pinscher.