1. Aguadé, M. & Serrra, L., 1980. Spanish cellar populations of Drosophila melanogaster. I. Study of variability at three different levels: quantitative, chromosomal and molecular. Genetika 12: 111?120.
2. Barnes, B. W., 1968. Stabilising selection in Drosophila melanogaster. Heredity 23: 433?442.
3. Beardmore, J. A. & Shami, S. A., 1976. Parental age, genetic variation and selection. In: S., Karlin & E., Nevo (eds), Population genetics and ecology, Academic Press, New York pp. 3?22.
4. Beardmore, J. A. & Shami, S. A., 1979. Heterozygosity and the optimum phenotype under stabilising selection. Aquilo, Ser. Zool. 20: 100?110.
5. Caligari, P. D. S., 1981. The selectively optimal phenotypes of the coxal chaetae in Drosophila melanogaster. Heredity 47: 79?85.