1. Azuma M. 1970. Studies on the variability of the landlocked ayu-fish,Plecoglossus altivelis T. et S., in Lake Biwa I. On the mode of distribution and some body form variation at early phases of development. Japan. J. Ecol., 20: 63–76. (In Japanese with English synopsis.)
2. Azuma, M. 1973a. Studies on the variability of the landlocked ayu-fish,Plecoglossus altivelis T. et S., in Lake Biwa II. On the segregation of population and the variations in each population. Japan. J. Ecol., 23: 126–139. (In Japanese with English synopsis.)
3. Azuma, M. 1973b. Studies on the variability of the landlocked ayu-fish,Plecoglossus altivelis T. et S., in Lake Biwa IV. Considerations on the grouping and features of variability. Japan. J. Ecol., 23: 255–265. (In Japanese with English synopsis.)
4. Calow, P. and A. S. Woollhead. 1977. The relationship between ration, reproductive effort and agespecific mortality in the evolution of life-history strategies—some observations on freshwater triclads. J. Anim. Ecol., 46: 765–781.
5. Iguchi, K. 1993. Latitudinal variation in ayu egg size. Nippon Suisan Gakkaishi, 59: 2087.