Widiyono, Eddy, et al. “Engineering Design of A Gang Drilling Machine Equipped With Jig and Fixtures to Make A Prototype Machine in Birdcage Production”. IPTEK The Journal for Technology and Science, vol. 22, no. 4, July 2025, pp. 214-20, https://journal.its.ac.id/index.php/jts/article/view/5644.