Autore:Friedrich Albert Lange
![](http://upload.wikimedia.org/wikipedia/commons/thumb/5/5a/Friedrich_Albert_Lange.jpg/140px-Friedrich_Albert_Lange.jpg)
- ↑ Bibliothèque nationale de France
- ↑ Encyclopædia Britannica
- ↑ 3,0 3,1 Internet Philosophy Ontology project
- ↑ Marburger Professorenkatalog
- ↑ Brockhaus Enzyklopädie
- ↑ Pedagogues and Psychologists of the World
- ↑ Store norske leksikon