Kolchin, P. (1987). Unfree labor: American slavery and Russian serfdom. Belknap Press of Harvard University Press.
Lua i Stíl Chicago (17ú heag.)Kolchin, Peter. Unfree Labor: American Slavery and Russian Serfdom. Cambridge, MA: Belknap Press of Harvard University Press, 1987.
Lua MLA (9ú heag.)Kolchin, Peter. Unfree Labor: American Slavery and Russian Serfdom. Belknap Press of Harvard University Press, 1987.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.