Asimov, I. (2016). Prelude to foundation. Harper Collins.
Chicago-čujuhus (17. p.)Asimov, Isaac. Prelude to Foundation. London: Harper Collins, 2016.
MLA-čujuhus (9. p.)Asimov, Isaac. Prelude to Foundation. Harper Collins, 2016.
Muitte dárkkistit čujuhemiid riektatvuođa, ovdal go geavahat daid iežat deavsttas.