Nuhu Issaka, R. (2012). Soil Fertility. IntechOpen.
Chicago-čujuhus (17. p.)Nuhu Issaka, Roland. Soil Fertility. IntechOpen, 2012.
MLA-čujuhus (9. p.)Nuhu Issaka, Roland. Soil Fertility. IntechOpen, 2012.
Muitte dárkkistit čujuhemiid riektatvuođa, ovdal go geavahat daid iežat deavsttas.