1. CROW, E., and SHIMIZU, K., 1988, Lognormal Distributions: Theory and Applications (New York: Marcel Dekker)
2. GOLDMAN-EISLER, F., 1968, Psycholinguistics: Experiments in spontaneous speech (New York: Academic Press)
3. JOHNSON, N., and KOTZ, S., 1970, Distributions in Statistics: Continuous Univariate Distributions (Boston, MA: Houghton-Mifflin Company)