Two mutual inductance bridges are described for operation up to about 100 kHz. Special attention is paid to the sensitivity and resolution of the bridges. Both bridges can be used to measure variations of about 10 pH in the mutual inductance. The first bridge consists of passive elements only whereas the second bridge is equipped with active circuits.
Flokstra, J., Gerritsma, G. J., Kreuwel, H. J. M., & van der Marel, L. C. (1980). Two high-frequency mutual inductance bridges with high resolution. Journal of physics E: scientific instruments, 13(10), 1071. https://doi.org/10.1088/0022-3735/13/10/008