Tanaka, Y. Paruvusu to senshinkoku kakumei, 1989 t.p. (Paruvusu) p. 1 (real name: Israel Lagarevich Helphand; 1867-1924)
Heresch, E. Geheimakte Parvus, c2000 p. 9 (Israil Lasarewitsch Helphand alias Alexxander Parvus)
Wikipdia, viewed 11 April 2013 Alexander Lvovich Parvus (Russian: Алекса́ндр Льво́вич Па́рвус), born Israel Lazarevich Gelfand (Russian: Изра́иль Ла́заревич Ге́льфанд) (1867-1924), was a Marxist theoretician, revolutionary, and a controversial activist in the Social Democratic Party of Germany. He also is said to have acted as a German intelligence agent.