1. For reviews see: Photomorphogenesis, Encyclop. Plant Physiol.16 (1983).
2. Falk H., Grubmayr K., Kapl G., M�ller N., Zrunek U., Monatsh. Chem.114, 753 (1983).
3. Kratky C., Falk H., Zrunek U., Monatsh. Chem.116, 607 (1985).
4. R�diger W., Structure and Bonding40, 101 (1980), and references therein.
5. Sheldrick G. M., SHELX 76, a program for crystal structure determination, University of Cambridge, England;Stewart G. M., the X-Ray system version of 1976. TR-466, CSS, University of Maryland, U.S.A.;Motherwell S., program PLUTO, University of Cambridge, England;Johnson C. K., ORTEP report ORNL 5138, Oak Ridge National Laboratory, Oak Ridge, Tennessee, U.S.A. (1976).