There is a biography entry, according to Google Books (only a snippet view is provided), in Wier (1938), The Macmillan encyclopedia of music and musicians. Student of (Hans?) Koessler.
- Most sources have 1935 as year of death, which is impossible as the uploaded Meditation is signed July, 12th 1939. According to the diary of his nephew, the composer Stephan Cosacchi (1903-1986) Jaray-Janetschek died on February, 9th 1945 in Budapest.
- His birth name is Stephan Janetschek, which he changed to Stephan Jaray-Janetschek to have a 'more hungarian' name, which he again changed to Istvan 1939 when the 2nd WW started and a German name was no longer acceptable.