Posen, M. (2003). Question and Answer Encyclopedia: The natural World. Parragon Publishing.
Chicago-čujuhus (17. p.)Posen, Michael. Question and Answer Encyclopedia: The Natural World. Bath Bai IHE, Inglaterra: Parragon Publishing, 2003.
MLA-čujuhus (9. p.)Posen, Michael. Question and Answer Encyclopedia: The Natural World. Parragon Publishing, 2003.
Muitte dárkkistit čujuhemiid riektatvuođa, ovdal go geavahat daid iežat deavsttas.