Zhonghua Ma, Dejun Liu, Hui Li & Xinsheng Gao. (1970). Numerical Simulation of a Multi-Frequency Resistivity Logging-While-Drilling Tool Using a Highly Accurate and Adaptive Higher-Order Finite Element Method. Advances in Applied Mathematics and Mechanics. 4 (4). 439-453. doi:10.4208/aamm.10-m11158