1. S.G. Roh, S.M. Ryew, H.R. Choi, “Development of differentially driven in-pipe inspection robot for underground gas pipelines”, Proc. of Int. Symposium on Robotic, 2001, pp.165-170.
2. S. Hirose, H. Ohno, T. Mitsui, and K. Suyama, “Design of in-pipe inspection vehicles for -25, -50, -150 pipes”, Proc. of IEEE Int. Conf. Robotics, Automation, 1999, pp. 2309-2314.
3. S.G. Roh and H.R. Choi, “Differential-Drive In-Pipe Robot for Moving Inside Urban Gas Pipelines”, IEEE Transactions on Robotics, vol. 21, no. 1, 2005, pp. 1-17.
4. M. Bernardi, H. Bley and B. Schmitt, “Integrating a mechatronics-oriented development process into a development department” Proceedings of the 37th CIRP International Seminar on Manufacturing Systems, 2004, pp. 265-27.
5. H.T. Roman, B.A. Pellegrino, W.R. Sigrist, “Pipe crawling inspection robots: an overview”, IEEE Transaction on Energy Conversion, vol. 8, no. 3, 1993, pp. 576-583.