It is very 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 (such as 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 with no "restoration" under the GATT amendments, it is very likely to be public domain in the USA as well.
|Composition Year||1959 February 1|
|Genre Categories||; ; ; ; ; ; ; ;; ; ;|
|Alternative. Title||Nonet "No.2"|
|Opus/Catalogue NumberOp./Cat. No.||H.374|
|Year/Date of CompositionY/D of Comp.||1959 February 1|
|First Performance.||1959 July 27, Salzburg, Czechoslovak Nonet|
|Composer Time PeriodComp. Period||Modern|
|Instrumentation||Flute, Oboe, Clarinet, Bassoon, Horn, Violin, Viola, Cello and Bass|
The composer wrote two nonets; an early unpublished (and rarely-performed) H.144 (1925, Paris), and the better-known H.374 of 1959. One way to tell: H.144 has a piano part. I can only see the first page of this work here, but there is no piano part. I think that's fairly good evidence.