1. E. Laviron and P. Zuman, unpublished results.
2. O. Manousek and P. Zuman, Chem. Commun. (London), (1956) 158.
3. P. Zuman and O. Manousek, Collection Czech. Chem. Commun., in the press.
4. O. Manousek, O. Exnbr and P. Zuman, Collection Czech. Chem. Commun., in the press.
5. P. Zuman, Collection Czech. Chem. Commun., 25 (1960) 3225.