Informality currencies : a tale of Misha, his brigada and informal practices among Uzbek labour migrants in RussiaUrinboyev, Rustamjon; Polese, AbelJournal of contemporary Central and Eastern Europe2016 / p. 191-206 http://dx.doi.org/10.1080/0965156X.2016.1261215 Unreported employment and envelope wages in mid-transition : comparing developments and causes in the Baltic countriesMeriküll, Jaanika; Staehr, KarstenComparative economic studies2010 / 4, p. 637-670 https://www.researchgate.net/publication/46133587_Unreported_Employment_and_Envelope_Wages_in_Mid-Transition_Comparing_Developments_and_Causes_in_the_Baltic_Countries Ümbrikupalga saajaks enda teadmata : [TTÜ doktorandi Kalle Kase firmast Trainator]Raidla, Peeter; Kask, KalleÄripäev2003 / 5. nov., lk. 23 https://arileht.delfi.ee/artikkel/6614075/umbrikupalga-saajaks-enda-teadmata