1. Henderson und Haggard, Americ. journ. of physiol. 1925, Bd. 73, Nr. 1.
2. H. Barcroft, Journ. of physiol. 1927, Bd. 63, Nr. 2.
3. Krogh und Lindhard Ebenda Journ. of physiol. 1917, Bd. 51.
4. Henderson,Ebenda Journ. of physiol. 1927, Bd. 62, Nr. 3.
5. Mobitz, Dtsch. Arch. f. klin. Med. 1927, Bd. 157, Hft. 5/6.