1. [AMRT] A. Ash, D. Mumford, M. Rapoport, and Y. Tai, Smooth compactification of locally symmetric varieties, Math. Sci. Press, Brookline, Mass., 1975, Lie Groups: History Frontiers and Applications IV.
2. [Hl] R.-P. Holzapfel, Ball cusp singularities, Nova Acta Leopoldina (N.F.) 52 (1981), no. 240, 109–117.
3. [Hr] F. Hirzebruch, Hilbert modular surfaces, Enseignement Math. (2) 19 (1973), 183–281.
4. [I] M. Inoue, New surfaces with no meromorphic functions II, Complex Analysis and Algebraic Geometry, Cambridge University Press, Cambridge, 1977, pp. 91–106.
5. [K] M. Kato, Compact complex manifolds containing `global' spherical shells, I, Proceedings of the Internat. Sympos. on Algebraic Geometry (Kyoto Univ., Kyoto, 1977), Kinokuniya Book Store, Tokyo, 1978, pp. 45–84.