Bose Majumdar, N.C.: On some properties of sets with positive measure. Annali dell’ Universita di Ferrara X. N1, p1 (1962), 1–11.
 Ganguly, D.K. and Majumdar, M: Some results on mid-point sets
. Journal of Pure Mathematics 7 (1990), 27–33. MR 1306645
 Ray, K.C.: On some properties of ratio sets
. Seminario mathematics del Universita di Ferrara, Sci VI (NS) (1962–65), 45–49. MR 0188366