Watts, S., & Halliwell, L. (1996). Essential environmental science: Methods & techniques. Routledge.
Chicago-čujuhus (17. p.)Watts, Simon, juo Lyndsay Halliwell. Essential Environmental Science: Methods & Techniques. New York: Routledge, 1996.
MLA-čujuhus (9. p.)Watts, Simon, juo Lyndsay Halliwell. Essential Environmental Science: Methods & Techniques. Routledge, 1996.
Muitte dárkkistit čujuhemiid riektatvuođa, ovdal go geavahat daid iežat deavsttas.