Teichmüller curves in moduli space, Eisenstein series and an application to triangular billiards. W.A. Veech — 1989 Inventiones mathematicae
Erratum: Teichmüller curves in moduli space, Eisenstein series and an application to triangular billiards. Invent. Math. 97, 553-583 (1989). W.A. Veech — 1991 Inventiones mathematicae