Armstrong, W. H. (1967). Study is hard work (2nd ed.). Harper $ row.
Chicago-čujuhus (17. p.)Armstrong, William H. Study Is Hard Work. 2nd ed. New York: Harper $ row, 1967.
MLA-čujuhus (9. p.)Armstrong, William H. Study Is Hard Work. 2nd ed. Harper $ row, 1967.
Muitte dárkkistit čujuhemiid riektatvuođa, ovdal go geavahat daid iežat deavsttas.