1. Siggaard-Andersen, O.: The Acid-Base Status of the Blood, 2nd ed. Baltimore, Williams and Wilkins, 1964, p. 55.
2. Comroe, J.H., Forster, R.E., DuBois, A.B., Briscoe, W.A. and Carlsen, E.: The Lung. Chicago, Year Book Medical Publishers, Inc., 1962, p. 339.
3. Mainland, D.: Elementary Medical Statistics, 2nd ed. Philadelphia, W. B. Saunders Co., 1964, p. 331.