3Richard PP,Mark PP.Sterile cover for intraoperative ultrasonic diagnostic devices and method and kit for providing same.US patent:4593699.1986-06-10.
4Doelker EL."Water-swollen cellulose derivatives in pharmacy",in hydrogels in medicine and pharmacy-polymers,edited by NA peppas.Boca Raton,Florida:CRC Press Inc,1987,11(2):115-161.
5Gilbert Bchalter.Method of transmitting ultrasonic impulses to surface using transducer coupling agent.US Patent:4002221.1977-01-11.
6Paul CA Richardson,Guildford.Ultrasonic transducer coupling member.US Patent:4459854.1984-07-17.
7Hiroshi Katsumata,Hiroyuki Yagami,Tadashi Fujii,et al.Ultrasonic coupler and method for production thereof.US Patent:5078149.1992-01-07.
8Marvin H.Gold,Sacramento,Calif.Water-based human tissue lubricant.US Patent:5342617.1994-04-30.
