Jonathon Hayt of Tucson, Arizona, supplied very useful information on sidecar manufacturers. emnjonh<at>comcast.net

Paul Markham of Australia and Eugene Smith of Arkansas supplied manuals for Heinkel, Durkopp, Progress and others.

From Australia, several images of KTM, Vespa and others from Byron Bay Motorcycles

Flat Tank Journey - images and information on Australian marques including Torpedo by Chas Hay & Son, and GCS.
Flat Tank Journey on FB

Immagina by Gyp of cyberium.net supplied numerous quality illustrations. (1)

Marius Pfister of Oldtimer Werkstatt, restorer of all manner of motorcycles, cars and antiques.

Rick Zolla, Montanaman

Roger Henderson, CZ/Jawa

Nathan Dodge scanned over a hundred pre-digital photos of classic bikes from various museums he made over a period of 20 years.

Axel Boehmert

Mike Christopher (Ariel, Omega, P&P)

Todd Koehn of Antigo, WI (BMW R100S)

Hans Smid. Information from his motorcycle archive at hanssmid.nl

Ton-up-Boys Australia supplied wonderful photos by the late Dave Morgan

Robert Livingstone, Puma Archive supplied a considerable amount of information on motorcycles built in Argentina.

Pekka Puoskari, a keen collector and restorer from Finland.

A number of quite fine photographs supplied by Gravitat-OFF

Mike Ricketts, collector and restorer, has documented many motorcycle museums and events in Europe. Mike Ricketts

Rene has taken photographs of European museums: Rene at Flikr

Kotomi supplied photos from Brooklands Museum: Kotomi at Flikr

Thanks to Doug Lyon for images made at the Glasgow Riverside Museum.