This may be redundant in light of Igor Pak's last comment, but I found an index for the 1918-1950 range in *The Otto Dunkel memorial problem book*, starting on page 80 of [this pdf][1]. [1]: https://docs.google.com/leaf?id=0B_pEp00B111JNjZjZjE1NGUtN2YwOC00OTUyLWE4NmYtNzEzY2VhMzk5Y2Iz&hl=en