References
- Oliver D. Anderson, The twenty-one card trick, Math. Gaz. 69 (1985) 188–190.
- Calvin T. Long, The twenty-seven card trick, Math. Gaz. 75 (1991) 299–303.
- Gabriela R. Sanchis, A card trick and the mathematics behind it, College Math. J. 37 (2006) 103–109.