- Bortstieber, Gertrud8
- Hanák, Péter3
- Nóvé, Béla2
- Radio Free Europe/Radio Liberty, Inc - Research Institute2
- Samizdat Archives2
- Balkan Section1
- Communist International (Comintern)1
- Curtius, Ernst Robert1
- Fischer, Kurt J.1
- Hegedüs, András1
- Heimbürger, Boris1
- Kautsky, Karl1
- Löwenthal, Richard1
- Magos-Gimes, Judit1
- Marx, Karl1
- Open Society Archives at Central European University1
- Pieck, Wilhelm1
- Romanian Unit1
- Rudzka, Marta1
- Samizdat Archives of Radio Free Europe1