Peter Riley. (2012). Cambridge Checkpoint Science Workbook 1 ("New, Workbook".). Hodder Education.
Chicago-čujuhus (17. p.)Peter Riley. Cambridge Checkpoint Science Workbook 1. "New, Workbook". Hodder Education, 2012.
MLA-čujuhus (9. p.)Peter Riley. Cambridge Checkpoint Science Workbook 1. "New, Workbook". Hodder Education, 2012.
Muitte dárkkistit čujuhemiid riektatvuođa, ovdal go geavahat daid iežat deavsttas.