1. Aoyagi, T., M. Kishi, K. Yamaguchi, and S. Watanabe. Improvement of an earpiece oximeter. Presented at 13th annual meeting of the Japanese Society for Medical Electronics and Biological engineering, Osaka, 1974.
2. Aoyagi, T., N. Kobayashi, and T. Sasaki. Apparatus for determining the concentration of a light-absorbing material in blood. US Patent No. US4832484 1989.
3. Boas, D. A., M. A. Franceschini, A. K. Dunn, and G. Strangman. Noninvasive imaging of cerebral activation with diffuse optical tomography. In: In Vivo Optical Imaging of Brain Function, edited by R. D. Frostig. Boca Raton: CRC Press, 2002, pp. 193–221
4. Dassel, C. Experimental Studies on Reflectance Pulse Oximetry: Specific Aspects of Intrapartum Fetal Monitoring. Doctoral thesis. RUG, Groningen, 1997, p. 157.
5. Eberhart, R. C., and A. Shitzer. Volume 1, Chapter 1: Introduction. In: Heat transfer in medicine and biology: Analysis and applications, edited by A. Shitzer, and R. C. Eberhart. London: Plenum Press, 1985, pp. 2–4.