APA-čujuhus (7. p.)
Soike, L. J. (2013). Necessary courage: Iowa's Underground Railroad in the struggle against slavery. University of Iowa Press.
Chicago-čujuhus (17. p.)
Soike, Lowell J. Necessary Courage: Iowa's Underground Railroad in the Struggle Against Slavery. Iowa City: University of Iowa Press, 2013.
MLA-čujuhus (9. p.)
Soike, Lowell J. Necessary Courage: Iowa's Underground Railroad in the Struggle Against Slavery. University of Iowa Press, 2013.
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