?


Werner
Sommer

Humboldt University Berlin


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


Jean
Piaget

University of Geneva


Bärbel
Inhelder

University of Geneva


Ernst
Boesch

University of Saarland


Paul
Baltes

Max Planck Institute for Human Development (Berlin)


Reinhold
Kliegl

University of Potsdam

Olaf
Dimigen

Humboldt University Berlin
(Options)

Olaf DimigenX