- Héderváry, Claire de3,057
- Radio Free Europe/Radio Liberty Research Institute (RFE/RL Research Institute)835
- Columbia University School of International Affairs358
- Radio Free Europe/Radio Liberty, Inc - Research Institute14
- Soviet Red Archives6
- Samizdat Archives5
- Bortstieber, Gertrud4
- Pallai, Péter4
- Csákó, Mihály3
- Hanák, Péter3
- Balogh, Eva S.2
- Bíró, András2
- Nóvé, Béla2
- Open Media Research Institute2
- Open Society Archives at Central European University2
- Alfred A. Reisch1
- Analytic Research Department1
- Balkan Section1
- British Broadcasting Corporation, Written Archive Centre1
- Bulgarian Unit1