- Radio Free Europe/Radio Liberty Research Institute (RFE/RL Research Institute)4,302
- Radio Free Europe/Radio Liberty, Inc - Research Institute12
- Soviet Red Archives5
- Bortstieber, Gertrud4
- Pallai, Péter4
- Hanák, Péter3
- Samizdat Archives3
- Balogh, Eva S.2
- Biberman, Herbert J.2
- Nóvé, Béla2
- Open Media Research Institute2
- Alfred A. Reisch1
- Analytic Research Department1
- Balkan Section1
- British Broadcasting Corporation, Written Archive Centre1
- Bulgarian Unit1
- Communist International (Comintern)1
- Czechoslovak Unit1
- Fic, Victor M.1
- Fondation pour une entraide intellectuelle européenne, FEIE1