1. S. J. Choi. Gusuryak (a reprint). Shungshin Womens University Press, Seoul, Korea, 1983.
2. Y. H. Jun. Mysteries of mathematics: The order of the universe hidden in numbers. Dong-A Science, 14(7):68–77, 1999.
3. S. K. Lee, D. I. Seo, and B. R. Moon. A hybrid genetic algorithm for optimal hexagonal tortoise problem. In Genetic and Evolutionary Computation Conference, page 689, 2002.
4. D. E. Goldberg. Genetic Algorithms in Search, Optimization, and Machine Learning. Addison Wesley, 1989.
5. S. Forrest and M. Mitchell. Relative building-block fitness and the building-block hypothesis. In Foundations of Genetic Algorithms, volume 2, pages 109–126. Morgan Kaufmann, 1993.