The Normalized Total Gradient has neither clear physical meaning nor complete mathematic theory as its basis,and it can only search the experimental law in the case of two and three dimensions.The authors hold that it is benefitial to get to know whether the GH(z) has mathematic and physical foundation or not and that the one who uses the GH(z) must take a very cautious attitude.
蔡越虹, 蔡宗熹. 论“重力归一化总梯度法”中的问题[J]. 物探与化探, 1999, 23(1): 46-50.
Cai Yuehong, Cai Zongxi. A DISCUSSION ON THE PROBLEM OF NORMALIZED TOTAL GRADIENT. Geophysical and Geochemical Exploration, 1999, 23(1): 46-50.