At the age of 12 Bruno Rossati began working eleven hour days.
"Now, approaching 91, I find myself reminiscing about my youth, still riding my motorcycle every day.
Letter re Ladetto
A Brief History of the Marque
Sidecars manufactured by Hans Möllers, Bernerstr. 3, Essen-Stoppenberg. Production began in 1930, and his designs were licenced to other manufacturers including Steib. The AWD museum writes: "Stoppa sidecars, manufactured in Essen Stoppenberg, were built at AWD in the pre-war years." This probably indicates that they were built in Düsseldorf under licence.
The Stoppenberg factory was destroyed by allied bombing raids during the war, in 1943/44.
Möllers' successor was F.G. Boehmer, who continued production until 1960.
Sources: motor-lit-berlin.de, awdmuseum.de, gespann-lexikon.de, et al
N.B. Unrelated to the French motorcycle manufacturer, Stop.