SUN TSUNG-TANG, CHAING WEN-CHIA, SHUN LIEN-FONG, MAO TIN-FONG. EXPERIMENTAL INVESTIGATION AND IMPROVEMENT ON THE FUNDAMENTAL CHARACTERS OF ESR SPECTROMETER WITH FREQUENCY AND MAGNETIC FIELD MODULATIONJ. Acta Physica Sinica, 1965, 21(4): 866-874. DOI: 10.7498/aps.21.866