- Radio Free Europe/Radio Liberty Research Institute (RFE/RL Research Institute)2,451
- Héderváry, Claire de40
- Radio Free Europe/Radio Liberty, Inc - Research Institute19
- Soviet Red Archives8
- Samizdat Archives7
- Csákó, Mihály5
- Pallai, Péter4
- Hanák, Péter3
- Balogh, Eva S.2
- Bortstieber, Gertrud2
- Bíró, András2
- Nóvé, Béla2
- Open Media Research Institute2
- Open Society Archives at Central European University2
- Samizdat Archives of Radio Free Europe2
- Alfred A. Reisch1
- Analytic Research Department1
- Balkan Section1
- British Broadcasting Corporation, Written Archive Centre1
- Bulgarian Unit1