ISO Prolog (from INRIA)

Official ISO Prolog page

Is the ISO Prolog taken seriously?

ISO-PROLOG and the Warren Abstract Machine

Links to commercial and academic applications of LPA-Prolog

More links to commercial and academic applications of LPA-Prolog

The Prolog Adventure

List of predefined Prolog predicates

Win Prolog (LPA, Logic Programming Associates)

Amzi Prolog (Windows, Unix, Corba, Java)

GNU Prolog (GNU/Linux). See also the official GNU Prolog site.

GNU Prolog for JAVA

JIProlog: Java Internet Prolog, a Java based Prolog

tuProlog: Java based Prolog

INRIA ISO Prolog Web (INRIA is strongly associated to the Gnu Prolog freeware)

SICStus Prolog (Windows, Unix, Linux)

SWI Prolog (Free ware, open source Prolog for Windows and Linux)

Prolog Implementations (Commercial, Free, for JAVA)