Keith Devlin (Stanford University, Stanford, California, USA)

Raymond Smullyan

Iqbal H. Jebril (Associate Professor, Department of Mathematics, Ta
Hemen Dutta
Ilwoo Cho (St. Ambrose University)

Torkel Franzen

Herbert B. Enderton (University of California, Los Angeles, U.S.A.)

David Angell (Australia Univeristy of New South Wales)

Alexandr Draganov

Alexandr Draganov