Configuration space of 8 points on the projective line and a 5-dimensional Picard modular group Keiji Matsumoto, Masaaki Yoshida (1993) Compositio Mathematica
Correction to "Two Generator Fuchsian Groups of Genus One". Gerhard Rosenberger, Norman Purzitsky (1973) Mathematische Zeitschrift
Correspondence of Modular Forms to Cycles Associated to Sp (p, q). S.P. Wang (1986) Mathematische Zeitschrift