Websites on Pestalozzi's Theory

https://www.heinrich-pestalozzi.de/

The most comprehensive online resource on Pestalozzi’s writings available in 9 different languages including Pestalozzi’s Letters on Early Education in the original German

http://bruehlmeier.info/

A comprehensive presentation of Arthur Brühlmeier's excellent writing on Pestalozzi

http://www.centrepestalozzi.ch/accueil

Centre of Information and Research on Pestalozzi at Yverdon

https://en.wikipedia.org/wiki/Johann_Heinrich_Pestalozzi