William Wallace
Campbell

Lick Observatory




Robert Stanley
Alexander

Washburn University


Bart J.
Bok

University of Arizona


Frank Kelley
Edmondson

University of Indiana


Arthur
Young

San Diego State University
?




Paul B.
Etzel

San Diego State University


Wander Johannes
de Haas

Leiden (Physics Tree)




Paul
Ehrenfest

Leiden (Physics Tree)








Bart J.
Bok

University of Arizona




Russel Kent
Honeycutt

Indiana University Bloomington (Physics Tree)

Jeff W
Robertson

Indiana University Bloomington
(Options)

Jeff RobertsonX