An interface circuit for R-C impedance sensors with a relaxation oscillator. - Stoyan N. Nihtianov; Georgi P. Shterev; Blagoy P. Iliev; Gerard C. M. Meijer (IEEE Trans. Instrum. Meas., 2001)

Extending the Limits of a Capacitive Soil-Water-Content Measurement. - Zu-yao Chang; Blagoy P. Iliev; J. F. de Groot; Gerard C. M. Meijer (IEEE Trans. Instrum. Meas., 2007)