Sawyer, W. W., A Concrete Approach to Abstract Algebra (1959) Sayeki, Hidemitsu, Some Consequences of Normality of the Space of Models Scarpellini, B., Bemerkungen zu Regel und Schema (1974) Scarpellini, Bruno, A Model of Intuitionistic Analysis (1970) Scarpellini, Bruno, Proof Theory and Intuitionistic Systems (1971) Scarpellini, Bruno, On Cut Elimination in Intuitionistic Systems of Analysis Schaefer, David H., A Rectifier Algebra (1954) Schaefer, Thomas Jerome, The Complexity of Some Two-Person Perfect-Information Games (1978) Schaeffer, K. H., A Methodology for Modeling in General Systems Studies (1960) Schaffter, Thomas L., On the Adequacy of a Nominalistic Mathematics for the Empirical Sciences (1975)