1. M. Butler, Grothendieck groups and almost split sequences. LNM882, 357?368, Berlin-Heidelberg-New York 1981.
2. C. W.Curtis and I.Reiner, Methods of Representation Theory I, II. New York-London-Sidney 1981, 1987.
3. A. Heller andI. Reiner, Grothendieck groups of integral group rings. Illinois J. Math.9, 349?360 (1965).
4. S.Langkopf Grothendieck-Gruppen von Ordnungen. Diplomarbeit, Stuttgart 1988.
5. I.Reiner, Maximal orders. New York-London 1975.