Changes

* [https://groups.google.com/d/msg/rec.games.chess.computer/1uVIWZFB41k/VUcAUkzyFd0J Fractional depth increments] by S. Read, [[Computer Chess Forums|rgcc]], January 18, 1996

* [https://www.stmintz.com/ccc/index.php?id=12201 "Suspicious move" extension] by [[David Eppstein]], [[CCC]], November 20, 1997

* [https://www.stmintz.com/ccc/index.php?id=17954 Move Extensions] by [[Roberto Waldteufel]], [[CCC]], May 04, 1998

* [https://www.stmintz.com/ccc/index.php?id=20167 Extend or not extend in a nullmove tree] by [[Roland Pfister]], [[CCC]], June 08, 1998 » [[Null Move Pruning]]