A. K. Sahakyan and R. R. Kamalian, “INTERVAL VERTEX-COLORINGS OF CACTUS GRAPHS WITH RESTRICTIONS ON VERTICES”, Proc. YSU A: Phys. Math. Sci., vol. 55, no. 3 (256), pp. 160–168, Nov. 2021, doi: 10.46991/PYSU:A/2021.55.3.160.