In earlier papers C. Dartyge and A. Sárközy presented large families of pseudorandom subsets with prime moduli. In this paper we extend two large families of subsets to the case when the moduli is composite.
"Pseudorandom subsets with composite moduli." Bull. Belg. Math. Soc. Simon Stevin 22 (3) 353 - 375, august 2015. https://doi.org/10.36045/bbms/1442364584