It may be a trivial point, but given the importance of dates around 1923 regarding copyright law in the United States, I believe Grove lists the original Ruralia Hungarica for piano as having been completed in 1924.
If and when we upload this score (and the poet Victor/Viktor Heindl whose words are set here, also provided the libretto for Tante Simona op.20 (1912), also for two songs (1911) by Jan Brandts Buys that are at BSB, (for other works besides I don't doubt...) - there is a mystery (to me anyway) when this Austrian lawyer (his day job :) ) and friend of Dohnányi's did die. Relevant to copyright questions, anyway! Eric 17:00, 8 November 2010 (UTC)