1. Structures Algébriques; Éléments de Mathématique IV, Premiére Partie, Livre II, Chap. I;Bourbaki,1951
2. On the immersion of an algebraic ring into a field;Malcev;Mathematische Annalen,1937
3. Distinct elements in a set of sums, (solution of a problem proposed by L. Moser);Scherk;American Mathematical Monthly,1955
4. A proof of the fundamental theorem on the density of sums of sets of positive integers;Mann;Annals of Mathematics,1942
5. Lattice Theory;Birkhoff,1948