1. Burns PN, Powers JE, Fritzsch T. Harmonic imaging, a new imaging and Doppler method for contrast enhanced ultrasound. Radiology 1992; 185: 142.
2. de Jong N, ten Cate F, Lance C. Principles and recent developments in ultrasound contrast agents. Ultrasonics 1991; 29: 324–30.
3. Holz K, Becker R, Schürmann R. Ultrasound in the investigation of tubal patency in infertile women. A meta-analysis of three comparative studies of Echovist® 200. in press.
4. Degenhardt F, Jibril S, Eisenhauer B. Hysteringo-Contrast Sonography (HyCoSy) for determining tubal patency. Clin Radiol 1996; 51 (1): 15–18.
5. Burns PB. Potential advantages of harmonic imaging. Advances in Echo-Contrast 1994; 4: 17–19.