1. Bergmann, F. 1987. Characterization of multiclonal aspen cultivars using isozyme electrophoresis. For Ecol & Manag, 22, 167–172.
2. Bugala, W. 1967. Populus nigra L. Arboretum Kornickie, 12, 1–220.
3. Cagelli, L, and Lefevre, F. 1995. Conservation of Populus nigra L and gene flow with cultivated poplar species in Europe. Forest Genet, in press.
4. Chakraborty, R, and Leimar, O. 1987. Genetic variation within a subdivided population. In: Ryman, N, and Utter, F. (eds) Population Genetics and Fishery Management, pp. 89–120. University of Washington Press, Seattle.
5. Clayton, J W, and Tretiak, D N. 1972. Amine-citrate buffers for control in starch gel electrophoresis. J Fish Res Board Can, 29, 1169–1172.