Walker Sally M. (2008). Early Bird Physics Screws. Lerner.
Chicago-čujuhus (17. p.)Walker Sally M. Early Bird Physics Screws. UK: Lerner, 2008.
MLA-čujuhus (9. p.)Walker Sally M. Early Bird Physics Screws. Lerner, 2008.
Muitte dárkkistit čujuhemiid riektatvuođa, ovdal go geavahat daid iežat deavsttas.