Ian Richards, On the classification of noncompact surfaces, Transactions of the American Mathematical Society 106 (1963), no. 2, 259-269. [OpenAIRE]
Rodrigo Treviño, On the ergodicity of flat surfaces of finite area, Geometric and Functional Analysis 24 (2014), no. 1, 360-386.
William A. Veech, Teichmüller curves in moduli space, Eisenstein series and an application to triangular billiards, Inventiones Mathematicae 97 (1989), no. 3, 553-583.