1. Digital filters;Ackroyd,1973
2. Modern techniques of power spectrum estimation;Bingham;IEEE Trans. BioMed. Eng.,1967
3. Fourier analysis of time series;Bloomfield,1976
4. Ultradian rhythms in the human fetus during the last ten weeks of gestation: an overview;Campbell;Sem. Perinat.,1980
5. Human Circadian Rhythms;Conroy,1970