| References |
|---|
| Arti et Amicitiae | Visual artists Society Amsterdam | › Arti |
| Art in Context | Center for Communications New York | › Art in Context |
| Artists and Art | The major modern & contemporary visual artists online | › the Artists |
| Artnews | Information on Contemporary Art | › Artnews |
| British Wittgenstein Society | providing a British focal point for research and exchange of ideas among Wittgenstein scholars | › BWS |
| Galeries.nl | Dutch database for visual art online | › GNL |
| Koninklijke Bibliotheek | National library of the Netherlands | › KB |
| Mensa International Dutch Mensa Association |
This organisation protects the interests an encourages the contact between intellectually highly gifted people | › Mensa Int › Mensa Ned |
| PhilPapers | Online research in philosophy | › PhilPapers |
| Pictoright Foundation | Protecting copyright and royalties | › Pictoright |
| Artists Rights Society | › ARS |
| Rijksbureau voor Kunst- historische Documentatie |
Netherlands Institute for Art History, Den Haag | › RKD |
| Wittgenstein Archives Bergen (Norway) |
Free online access to Wittgenstein primary sources | › WAB |