1. Brieger, F G. 1935. Genetic analysis of the cross between the self-fertile Nicotiana langsdorffii and the self-sterile N. sandarae. J Genet, 30, 78–100.
2. Butenko, R G, and Luneva, M Z. 1966. The application of the sterile culture technique for the cultivation of distant hybrids of Nicotiana. Fiziol Rast, 13, 733–736.
3. Cocking, E C. 1977. Genetic modification of plant cells: a reappraisal. Nature, 266, 13–14.
4. Fincham, J R S, and Sastry, G R K. 1974. Controlling elements in maize. Ann Rev Genet, 8, 15–50.
5. Hess, D. 1977. Cell modification by DNA uptake. In Plant Cell, Tissue and Organ Culture, eds. J. Reinert and Y. P. S. Bajaj, pp. 506–577. Springer-Verlag, Berlin-Heidelberg.