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| | RussianSpaceWeb.com sources |
 | | Semenov, Y., RKK Energia Imeni S.P. Koroleva (in Russian), 1996 |
 | | Semenov, Y., RKK Energia Imeni S.P. Koroleva, Na Rubezhe Dvukh Vekov 1996-2001 (in Russian), 2001 |
 | | This date is according to V.M. Filin, S.P. Korolev Space Corporation Energia: From First Satellite to Energia-Buran and Mir. |
| www.russianspaceweb.com /sources.html (2601 words) |
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