I would recommend Ivo's book, which covers the basic details of ten Hoffmann's including Josef. He is quite important. The factory in Gablonz was set up in 1900 for pressed glass. Curt Schlevogt got involved c1934. For some reason that bit is not in Ivo's book, his life looks very complicated with all of THE names in glass mentioned. Most of the info I have is in German which I cannot translate easily and is in Hartmann, Glasmarken Lexicon. Unlike Ivo's book it costs an arm and a leg.Miller's Glass Fact File a-z
a contemporary guide to artists, factories and techniques
by Ivo Haanstra, (C) 2001 Octopus Publishing Group Ltd.
ISBN 1840004290 retail UKP 7,99 (USA $12,95)
You can find a link to it in Ivo's post in our author's thread http://www.glassmessages.com/index.php/topic,2066.0.html
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