see also Holdsworth - Aids to Happy Cycling

1. Date: 1949
   

2. Derailleur brands: Constrictor, Cyclo Gear Company, GB, Huret, Osgear, Resilion, Simplex, TriVelox
   

3. Derailleurs: too many to mention
   

see also H. H. England - Cycling Manual

1. Date: 1960
   

2. Derailleur brands: BSA, Cyclo Gear Company, Osgear, Resilion, Simplex, Sturmey-Archer, Super Champion
   

3. Derailleurs: Cyclo Benelux, Resilion Crimson Star, Simplex Juy 59