1. [1] L.L. Larmore and D.S. Hirschberg, “Length-limited coding,” Proc. SODA '90, pp.310-318, 1990.
2. [2] H. Fujiwara and T. Jacobs, “On the huffman and alphabetic tree problem with general cost functions,” Algorithmica, vol.69, no.3, pp.582-604, 2014.
3. [3] D.A. Huffman, “A method for the construction of minimum-redundancy codes,” Proc. Institute of Radio Engineers, pp.1098-1101, 1952.
4. [4] L.L. Larmore and T.M. Przytycka, “A fast algorithm for optimum height-limited alphabetic binary trees,” SIAM J. Comput., vol.23, pp.1283-1312, 1994.
5. [5] L.G. Kraft, A device for quantizing, grouping, and coding amplitude modulated pulses, Master's thesis, Massachusetts Institute of Technology, 1949.