1. Ziegler, K., Holzkamp, E., Breil, H., Martin, H.: Angew. Chem. 67, 541 (1955).
2. Boor, J.: Macromolecular Reviews, Vol. II, p. 115. New York, N. Y.: John Wiley and Sons 1967.
3. Gaylord, N. G., Mark, H. F.: Linear and Stereoregular Addition Polymers. New York-London: Interscience Publ. Inc. 1959.
4. Reich, L., Schindler, A.: Polymerization by Organometallic Compounds. New York-London: John Wiley and Sons 1966.
5. Natta, G.: J. Polymer Sci. 16, 143 (1955).