1. Astrup P, Severinghaus JW. The history of blood gases, acids and bases. Copenhagen: Munksgaard, 1986:332pp
2. Severinghaus J, Astrup P: History of blood gas analysis. VI. Oximetry. J Clin Monitoring 1986;2:270–288
3. Petersen J: The development of pulse oximetry. Science 1986;232:G135–136
4. Millikan GA: The Oximeter, an instrument for measuring continuously oxygen saturation of arterial blood in man. Rev Scient Instr 1942;13:434–444
5. Wood E, Geraci JE: Photoelectric determination of arterial oxygen saturation in man. J Lab Clin Med 1949;34:387–401