References
- Holton , D . 2009 . The frog problem: More than you might want to know . Math. Gaz. , 93 ( 528 ) : 398 – 403 .
- Holton , D , Ahmed , A , Williams , H and Hill , C . 2001 . On the importance of mathematical play . Int. J. Math. Educ. Sci. Technol. , 32 ( 3 ) : 401 – 415 .