1. Int. Astron. Union Symp.,1974
2. Galaxies and the Universe (Sandage, A., Sandage, M., Kristian, J., eds.),=Stars and Stellar Systems Vol. IX, Univ. Chicago Press (1975).
3. Freeman, K., Larson, R.B., Tinsley, B.M.: Galaxies, Sixth advanced course of Swiss Soc. of Astron. and Astrophys. (Martinet, L., Major, M., eds.), Geneva Observatory (1976).
4. Int. Astron. Union Symp.,1978
5. Taylor, R.J.: Galaxies, Structure and Evolution, Wykeham Publ. Ltd., London (1978).