M. G. Abrenica, J. Alba, P. M. Dumago, M. Evangelista, J. Monreal, and K. A. Seciban, “Development, Evaluation and Heavy Metal Analysis of Tailor’s Chalk Using Eggshell and Green Apple Snail Shell in Three Formulations”, IJERIP, vol. 2, no. 5, pp. 1125–1134, May 2026, doi: 10.5281/zenodo.20324229.