Four Jewish prisoners at Potma in the Mordovian Republic–Boris Penson, Hillel Shur, Arkady Shpilberg and Lassal Kaminsky were illegally removed from that camp April 4 and confined to the prison in Saransk, also in the Mordovian Republic, apparently to isolate them, according to Jewish sources in the Soviet Union. The four were sentenced to terms in a labor camp, not a prison. The sources also reported that 309 Soviet Jews have signed an appeal to Jewish communities and organizations for help in securing visas to Israel. Many of them have lost their jobs because of this and are under surveillance; others have been interrogated and warned but have signed anyway. The signers are from Moscow, Wilna, Riga, Talin, Kharkov, Kiev, Leningrad, Kishinev, Minsk, Sverdlovsk and Rostov.