1. On second order linear differential equations with algebraic solutions;Baldassarri;Amer. J. Math,1979
2. Introduction to the Theory of Algebraic Functions of One Variable, Mathematical Surveys, VI;Chevalley,1951
3. A Liouville principle for linear differential equations. Proc. Journées Equations Differentielles dans le Champ Complexe;Davenport,1986
4. Closed Form Solutions of Ordinary Differential Equations;Davenport,1984
5. Integration in finite terms;Davenport;SIGSAM Bull.,1984