An Implantable, Batteryless, and Wireless Capsule With Integrated Impedance and pH Sensors for Gastroesophageal Reflux Monitoring. - Hung Cao; Vaibhav Landge; Uday Tata; Young-Sik Seo; Smitha M. N. Rao; Shou Jiang Tang; Harry F. Tibbals; Stuart Spechler; Jung-Chih Chiao (IEEE Trans. Biomed. Eng., 2012)