Gopalkrishnan , R. (2010). When The Penny Drops: Learning What Not Taught. Penguin.
Chicago-čujuhus (17. p.)Gopalkrishnan , R. When The Penny Drops: Learning What Not Taught. Delhi: Penguin, 2010.
MLA-čujuhus (9. p.)Gopalkrishnan , R. When The Penny Drops: Learning What Not Taught. Penguin, 2010.
Muitte dárkkistit čujuhemiid riektatvuođa, ovdal go geavahat daid iežat deavsttas.