El mundo en la retorta : una química moderna para todos / Hans Joachim Flechtner; pref. Paul Karlson
Theory of alternating-current machinery / Alexander S. Langsdorf
Matter and light : the new physics / Louis de Broglie; trad. W. H. Johnston
TP 2000 : a projection on to the year 2000 compiled by the Ministry of Transport and Public Works of the Netherlands / Ministry of Transport and Public Works