History and Design of the Roskopf Watch
First published in 1914, this study of the Roskopf watch is the most comprehensive, providing a detailed biography of G.F. Roskopf and a thorough study of his watch calibres.
Buffat was a watchmaker who was the associate of and successor to G.F. Roskopf's son, F.E. Roskopf, and so in an excellent postion to write this book.
Those interested in Roskopf watches should also read Albin Schaeder "The Proletarian Watch" which provides an excellent pictorial survey of these watches and some additional material.