Citation: P. Pfleging et al., DIFFERENCES IN OSCILLATION FREQUENCIES BETWEEN 2 KEY ENZYMES OF AROMATIC AMINO-ACID CATABOLISM IN EUGLENA - CIRCADIAN RHYTHMICITY OF TRYPTOPHAN 2,3-DIOXYGENASE VS PREDOMINANCE OF ULTRADIAN PERIODS IN TYROSINE AMINOTRANSFERASE, Biological rhythm research, 25(1), 1994, pp. 59-66