1. 2 Fountain J. B. and Gould V. A. R. . Straight left orders in rings. Quart. J. Math. Oxford Ser. (2) (to appear).
2. 4 Gould V. A. R. . Straight left orders (Technische Hochschule Darmstadt, preprint).
3. Sul teorema di Goldie;Herstein;Atti Accad. Naz. Lincei Rend. Cl. Sci. Fis. Mat. Natur.,1963
4. Orders in rings without identity