Severinghaus, John W. (2007). «Takuo Aoyagi: Discovery of Pulse Oximetry». Ovid Technologies (Wolters Kluwer Health). Anesthesia & Analgesia. 105: S1–S4. ISSN0003-2999. doi:10.1213/01.ane.0000269514.31660.09
Severinghaus, John W. (2011). «Monitoring oxygenation». Springer Science and Business Media LLC. Journal of Clinical Monitoring and Computing. 25: 155–161. ISSN1387-1307. doi:10.1007/s10877-011-9284-2
Severinghaus, John W. (2007). «Takuo Aoyagi: Discovery of Pulse Oximetry». Ovid Technologies (Wolters Kluwer Health). Anesthesia & Analgesia. 105: S1–S4. ISSN0003-2999. doi:10.1213/01.ane.0000269514.31660.09
Severinghaus, John W. (2011). «Monitoring oxygenation». Springer Science and Business Media LLC. Journal of Clinical Monitoring and Computing. 25: 155–161. ISSN1387-1307. doi:10.1007/s10877-011-9284-2