Ah! Have some BA-MA indexes (saved from Internet); partial RL 20 index (I have) seems not listing these particular folders. Online search produced these:
http://startext.net-build.de:8080/ba...ize=20#Treffer
http://startext.net-build.de:8080/ba...gliederung.htm
http://startext.net-build.de:8080/ba...4110/index.htm
Now, how to use this for effective results... Any suggestions?