Likewise, experiencing JVM is something different from ALGOL ... And not quite sure if SQL could be grouped together with Prolog due to its declarative nature.

Likewise, experiencing JVM is something different from ALGOL ... And not quite sure if SQL could be grouped together with Prolog due to its declarative nature. But if so, DBMS is, like OTP, quite far from Prolog, just in a slightly different direction :) I guess what I'm trying to say is that the list of ur-languages seems quite fine to me.