Citations to Discrete Fourier Transform, Autocorrelation method, Enright periodogram, Lomb-Scargle periodogram and Sokolove-Bushell periodogram for the last 30 years.

<p>The figure was drawn from data in Scopus, checked in October 1st 2013. The search was limited to the subject areas of “Life Sciences” and “Health Sciences”. The search shows that the DFT and Autocorrelation methods are the most widely cited approaches and are on the rise. The Enright periodogram usage seemed to start declining once papers using the Lomb-Scargle periodogram started to increase. The search was performed using the keywords: “Oscillations”, “Rhythm” OR “Rhythms” in the article title, abstract or keywords; “method” in “All fields”; “Discrete Fourier Transform” OR “Fast Fourier Transform”, for the FFT or DFT methods; “Autocorrelation method”, for the Autocorrelation method; “Enright periodogram” OR “chi-square periodogram”, for the Enright method; “Lomb periodogram” OR “Lomb-Scargle periodogram” OR “Lomb” AND “Scargle”, for the Lomb periodogram; “Sokolove-Bushell periodogram” OR “Sokolove-Bushell” OR “Sokolove” AND “Bushell”, for the Sokolove-Bushell method.