Should article state that this work is now in public domain? How can this can be confirmed? edit

Since this work has been published in 1917 is it correct to state that it is in public domain right now? Should the article mention it? According to "How to Determine Whether a Work is in the Public Domain" it should be, regardless of whatever count one considers... however, I cannot find any confirmation of it anywhere, and this particular book is not in the Online books library. B.Trafficlight (talk) 03:39, 7 November 2015 (UTC)Reply