K. Watanabe, A. Mitsumori, H. Nishioka, and M. Koda. “In-situ Full Scale Load Tests and Reliability Evaluation of Bearing Capacity for Nodular Cast-in-place Concrete Pile”. Geotechnical Engineering Journal of the SEAGS & AGSSEA, vol. 48, no. 3, Sept. 2017, pp. 58-64, doi:10.14456/seagj.2017.6.