Perforated bone plates and string production in the Mesolithic: a case-study from site Stanovoye 4, Upper Volga - Zhilin, Mikhail ('Prehistoric technology'. 40 years later: functional studies and the Russian legacy. Wear-traces, ethnoarchaeology, experimental archaeology. Proceedings of the international congress, Verona (Italy), 20-23 april 2005., 2008)