References
- Kaiser I H, Halberg F. Circadian periodic aspects of birth. Ann NY Acad Sci 1962; 98: 1056–68
- Glattre E, Bjerkedal T. The 24-hour rhythmicity of birth. Acta Obstet Gynecol Scand 1983; 62: 31–36
- Charles E. The hour of birth. J Prev Soc Med 1953; 7: 43–59
- Bakketeig L S, Hoffmann H J, Titmuss, Oakley A R. Perinatal mortality. Perinatal epidemiology, M Bracken. Oxford University Press, New York 1984; 99–151
- Pecaud F, Martin-Beran B, Gutzwiller F. Hour of birth as a prognostic factor for perinatal death. Lancet 1988; i: 340–3
- Bergsjø P, Bakketeig L S, Bjerkedal T. Fødselsregistrering med partogram (Birth registration by partogram [in Norwegian, English summary]). Tidsskr Nor Laegeforen 1977; 95: 439–42
- Norusis M J. SPSS/PC+ Advanced statistics V2.0. SPSS Inc., Chicago 1988; III
- Armitage P. Statistical methods in medical research. Blackwell Scientific Publications, Oxford 1974
- Bergsjø P, Bakketeig L, Eikhorn S N. Duration of labor with spontaneous onset. Acta Obstet Gynecol Scand 1979; 58: 129–34
- Nesheim B I. Duration of labor. An analysis of influencing factors. Acta Obstet Gynecol Scand 1988; 67: 121–4