Hello. Get a copy of the ECRA 25th aniversary special issue1965-1990.It has an article by Werner Sunkel which is the best starting site on the 37x94R. With that knowledge, you can start the exciting hunt for more. It some times appears in other languages than English, but then there is the translation problem. So far, I have found rounds from 9 countries and there are more which I have not be lucky enough to find. Good luck, and drop me a line, I occaisionally have duplicates for trade or sale.