Those signing the greeting included Yelena Bonner, widow of Soviet-era dissident Andrei Sakharov, prominent human rights activist Sergei Kovalev as well as Aleksandr Nikitin and Grigorii Pasko, both of whom got jail terms in post-Communist Russia after drawing attention to environmental pollution.
Khodorkovskii, once Russia's richest man when he was owner of the Yukos oil company, is serving an 8-year prison term for fraud and tax evasion in the Siberian town of Krasnokamensk. Critics say his trial was engineered by the Kremlin.
RFE/RL Russia Report
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