-including lib/gslextras and the linear regression features. Jason
-is also an important contributor to GSL, which is used by PSPP.
+including lib/gslextras and the linear regression features. Jason
+is also an important contributor to GSL, which is used by PSPP.
+
+* Mehmet Hakan Satman provided the initial implementation of the QUICK CLUSTER command.
+ Alan Mead and others contributed later improvements including the cluster membership subcommands.
+
+* Friedrich Beckmann wrote the GRAPH command.