On generalized formal power series Alena Vanžurová (1986) Acta Universitatis Palackianae Olomucensis. Facultas Rerum Naturalium. Mathematica
On positive and critical theories of some classes of rings. Vazhenin, Yu.M., Popov, V.Yu. (2000) Siberian Mathematical Journal
On the Mulitplicity of Zeros of Polynomials over Arbitrary Finite Dimensional K-Algebras. F. Leon Pritchard (1984/1985) Manuscripta mathematica