[1]Wan Zhexian. Geometry of Classical Groups over Finite Fields. Studentlitteratur, Lund 1993

[2]Wan Zhexian. Further Studies on Singular Symplectic, Unitary, and Orthogonal Geometries over Finite Fields. World Science Publishing Company, SEA Bull Math, 1993, 17(2): 177-196

[3]Wan Zhexian. Anzahl Theorems in Finite Singular Symplectic, Unitary and Orthogonal Geometries.Discrete Math, 1993, 123:131-150

[4]Wei Hongzeng. Two Anzahl Theorems in Singular Orthogonal Geometry over Finite Field of Ch.6= 2 and A Class of PBIB Designs. Acta Mathematicae Applicatae Sinica, 1994, 17(3): 347-354