BIG ELEPHANT FOUNDATION. (2012). MIND TWISTER MATHS OLYMPIAD WORKBOOK- 4. BIG ELEPHANT FOUNDATION.
Chicago-čujuhus (17. p.)BIG ELEPHANT FOUNDATION. MIND TWISTER MATHS OLYMPIAD WORKBOOK- 4. BIG ELEPHANT FOUNDATION, 2012.
MLA-čujuhus (9. p.)BIG ELEPHANT FOUNDATION. MIND TWISTER MATHS OLYMPIAD WORKBOOK- 4. BIG ELEPHANT FOUNDATION, 2012.
Muitte dárkkistit čujuhemiid riektatvuođa, ovdal go geavahat daid iežat deavsttas.