In Soo Lee, Won-Sub Tae, Yoon-Soo Kim, Myung-hwan Jeong, Jong-Pil Seo, Kyung-Jin Na, Dong-Jin Sung and Soo-Young Ha  2017. State Monitoring System of Robot Welding Gun Based on ART2 Neural Networks. International Journal of Robotics and Automation Technology. 4, (Aug. 2017), 1–8. DOI:https://doi.org/10.15377/2409-9694.2017.04.1.