1. Stanford Encyclopedia of Philosophy
2. Internet Encyclopedia of Philosophy
3. Philosophica. Enciclopedia Filosófica on line
4. Biblioteca virtual Miguel de Cervantes
5. Enciclopedia Multimediale delle Scienze Filosofiche
6. Bibliotecha Augustana
7. Guide to Early Church Documents
8. Internet Medieval Sourcebook
9. Dictionary of Philosopy. Dagobert D. Runes
10. Biblioteche dei filosofi
11. Medieval Illuminated Manuscripts
