Original Authors and Contributors:

Joe Armstrong
Robert Virding
Mike Williams
Claes Wikström
Tony Rogvall
Magnus Fröberg
Martin Björklund
Björn Gustavsson
Patrik Nyblom
Arndt Jonasson
Kenneth Lundin
Peter Högfeldt
Torbjörn Törnkvist
Sebastian Strollo
Carl Wilhelm Welin
Lennart Öhman
Hans Bolinder
Raimo Niskanen
Rickard Green
Gunilla Arendt
Dan Gudmundsson
Peter Andersson
Ingela Anderton
Jakob Cederlund

and probably others...

Open source contributors:
Richard Carlsson and Sven-Olof Nyström: gb_trees and gb_sets
Richard Carlsson (several modules)