Willy
Hellpach

Heidelberg University (PsychTree)


Wilhelm
Witte

University of Regensburg, Germany


Fred
Attneave

University of Oregon


Richard K.
Olson

CU Boulder




John S.
Werner

UC Davis
?


Gene V.
Glass

Arizona State (EduTree)


Ernst
Boesch

Saarland University


Paul
Baltes

Max Planck Institute for Human Development (Berlin)


Reinhold
Kliegl

University of Potsdam


Ulrich
Mayr

University of Oregon


Wilhelm
Wundt

University of Leipzig


Willy
Hellpach

Heidelberg University (PsychTree)


Wilhelm
Witte

University of Regensburg, Germany
?


Fred
Attneave

University of Oregon


Richard K.
Olson

CU Boulder






John S.
Werner

UC Davis
?


Gene V.
Glass

Arizona State (EduTree)


Jean
Piaget

University of Geneva


Bärbel
Inhelder

University of Geneva


Ernst
Boesch

Saarland University


Paul
Baltes

Max Planck Institute for Human Development (Berlin)


Reinhold
Kliegl

University of Potsdam








Martin H.
Fischer

University of Potsdam, Germany (PsychTree)

Jochen
Laubrock

University of Potsdam, Germany
(Options)

Anke
Cajar

University of Potsdam, Germany

Jochen LaubrockX