R. Ray, P. Bhatt, N. Kaswan, G. Singh, D. Dave, and R. Soni, “Pens, Plastics, and Planet: A Study of Student Groups’ Plastic Pen Usage and Awareness of Its Impact on Environmental Sustainability”, Int. J. Ecol. Env. Sci., vol. 51, no. 4, pp. 437–447, Jun. 2025.