The representation of Boolean algebras
M. H. Stone · Bulletin of the American Mathematical Society · 1938
References by number are to the bibliography at the end.* Boolean rings without unit correspond likewise to certain simple generalizations of Boolean algebras [31 ], [32].* This field consists of two elements, 0 and 1, with the rules of operation 0 -0 = 0 -1 = 1 -0 = 0+0 = 1+1 = 0and 1-1 = 1+0 = 0+1 = 1.