References
- BALZER , I. and HARDELAND , R. 1992 . Multiple ultradian frequencies in dark motility of Euglena . J. Interdiscipl. Cycle Res. , 23 : 47 – 55 .
- BALZER , I. , NEUHAUS‐STEINMETZ , U. , QUENTIN , E. , VAN WÜLLEN , M. and HARDELAND , R. 1989 . Concomitance of circadian and circa‐4‐hour ultradian rhythms in Euglena gracilis . J. Interdiscipl. Cycle Res. , 20 : 15 – 24 .
- HALBERG , F. , CARANDENTE , F. , CORNELISSEN , G. and KATINAS , G.S. 1977 . Glossary of Chronobiology . Chronobiologia , 4 ( Suppl. 1 )
- HALBERG , F. , JOHNSON , E.A. , NELSON , W. , RUNGE , W. and SOTHERN , R. 1972 . Auto‐rhythmometry procedures for physiologic self‐measurements and their analysis . Physiol. Teacher , 1 : 1 – 11 .
- HARDELAND , R. and BALZER , I. 1992 . Ultradian rhythms as elements of multioscillator systems in Euglena gracilis and Tetrahymena thermophila . J. Interdiscipl. Cycle Res. , 23 : 196 – 198 .
- MORGEN , E. and MINORS , D.S. 1995 . The analysis of biological time series data: some preliminary considerations . Biological Rhythm Research , 26 : 124 – 148 .
- NEUHAUS‐STEINMETZ , U. 1988 . Zur Frage der Existenz ultradianer metabolischer Rhythmen bei circadian schwingenden Euglenen Göttingen Diploma thesis
- NEUHAUS‐STEINMETZ , U. , BALZER , I. and HARDELAND , R. 1990 . Ultradian rhythmicity of tyrosine aminotransferase activity in Euglena gracilis: Analysis by cosine and non‐sinusoidal fitting procedures . Int. J. Biometeorol. , 34 : 28 – 34 .
- PFLEGING , P. , MORAWIETZ , G. and HARDELAND , R. 1994 . Differences in oscillation frequencies between two key enzymes of amino acid catabolism in Euglena: Circadian rhythmicity of tryptophan 2,3‐dioxygenase vs. predominance of ultradian periods in tyrosine aminotransferase . Biol. Rhythm. Res. , 25 : 59 – 66 .
- POESCHE , W.H. 1982 . A non‐sinusoidal regression function for least square fitting of rhythmic data . J. Interdiscipl. Cycle Res. , 13 : 1 – 21 .
- SOLLBERGER , A. 1976 . Time series power or when is a cycle not a cycle . Cycles , 27 : 93 – 94 .
- SOLLBERGER , A. 1977 . Correlation and regression . Cycles , 28 : 163 – 166 .
- TONG , Y.L. , LEE , J.K. and HALBERG , F. 1973 . Number‐weighted mean cosinor technique resolves phase‐ and frequency‐synchronized rhythms with differing mesors and amplitudes . Int. J. Chronobiol. , 1 : 365 – 366 .
- I. Zoologisches Institut, Universität Göttingen, Berliner Str. 28, D‐37073 Göttingen, Germany.