Kolchin, P. (1987). Unfree labor: American slavery and Russian serfdom. Belknap Press of Harvard University Press.

Kolchin, Peter. Unfree Labor: American Slavery and Russian Serfdom. Cambridge, Massachusetts: Belknap Press of Harvard University Press, 1987.

Kolchin, Peter. Unfree Labor: American Slavery and Russian Serfdom. Belknap Press of Harvard University Press, 1987.