Riley, P. (2011). Cambridge Checkpoint Science 2 (1st.). Cambridge University Press.
Chicago-čujuhus (17. p.)Riley, Peter. Cambridge Checkpoint Science 2. 1st. London: Cambridge University Press, 2011.
MLA-čujuhus (9. p.)Riley, Peter. Cambridge Checkpoint Science 2. 1st. Cambridge University Press, 2011.
Muitte dárkkistit čujuhemiid riektatvuođa, ovdal go geavahat daid iežat deavsttas.