The universal highly stable sensing device with a zero temperature coefficient for the magnetometers, variometers and microvariometers recording any component of a terrestrial magnetic field,
Bobrov, V. N. (1961),
Terrestrial Magnetism of II. Theoretical Bases of a Magnetometric Research Technique of Crust and Geomagnetic Measurements, IZMIRAN, issue 18(28) p. 55–67