Märtens, O., T. Saar, M. Min, R. Land, and M. Reidla. 2010. “Fast Impedance Spectroscopy of Piezosensors for Structural Health Monitoring”. Elektronika Ir Elektrotechnika 103 (7):31-34. https://eejournal.ktu.lt/index.php/elt/article/view/9270.