- * Jason Stover contributed statistical and numerical
- functionality, including lib/gslextras. (Jason is also an
- important contributor to libgsl used by PSPP.)
+* Jason Stover contributed statistical and numerical functionality,
+including lib/gslextras. Jason is also an important contributor to
+GSL, used by PSPP.
+
+We also thank past contributors:
+
+* John Williams wrote an initial draft of the T-TEST procedure.
+
+* Michael Kiefte contributed bug fixes and other enhancements.
+
+* Patrick Kobly contributed bug fixes and other enhancements.