Author,Title,Journal,ISSN,Publisher,Date,Volume,Number,Page,URL,URL(DOI) K. Nakajima and T. Tamura and H. Miike,Monitoring of heart and respiratory rates by photoplethysmography using a digital filtering technique,Medical Engineering & Physics,1350-4533,Elsevier BV,1996-07,18,5,365-372,https://cir.nii.ac.jp/crid/1362825895130189440,https://doi.org/10.1016/1350-4533(95)00066-6