Inventions, H.234 (Martinů, Bohuslav)
It is unlikely that this work is public domain in the EU, or in any country where the copyright term is life-plus-70 years. However, it is in the public domain in Canada (where IMSLP is hosted) and other countries where the term is life-plus-50 years (like China, Japan, Korea and many others worldwide). As this work was first published before 1923 or failed to meet notice or renewal requirements to secure statutory copyright, it is very likely to be public domain in the USA as well.
First edition (reprint)
Prague: Melantrich, n.d.. Plate M 335.
Boca Raton: Edwin F. Kalmus, n.d.(after 1990). Catalog A 7431.