Ward, J. A., & Hetzel, H. R. (1980). Biology: Today and tomorrow. Minn West.
Chicago-čujuhus (17. p.)Ward, Jack A., juo Howard R. Hetzel. Biology: Today and Tomorrow. St. Paul.: Minn West, 1980.
MLA-čujuhus (9. p.)Ward, Jack A., juo Howard R. Hetzel. Biology: Today and Tomorrow. Minn West, 1980.
Muitte dárkkistit čujuhemiid riektatvuođa, ovdal go geavahat daid iežat deavsttas.