James Clark:
Original author of the SP suite, from which OpenSP is derived.

Henry Thompson:
Initial autoconf support for SP.

Cees A. de Groot:
Autoconf support for SP.

Matthias Clasen:
spcat, DTDDECL, CONCUR, improved support of Annex K, 
autoconf & automake setup.

Peter Newcomb, Epremis Corp.:
MessageModule, support for HyTime Amendment 1 (IS10744:arch PI)