Kochmann, Karl: Clock and Watch Trademark Index. European Origin. Austria, England, France, Germany, Switzerland
1992, Generally Revised/Enlarged Edition 1000. Concord (CA): Antique Clocks Publishing, 1988
ISBN 0-933396-27-9.
This work is the most important reference work for stampings on clock movements of the 19th and early 20th century. It comprehensively documents the trademarks of clock manufacturers from Austria, England, France, Germany and Switzerland and thus enables the reliable identification of manufacturers and factory marks.