How to read and interpret USG images

http://books.google.co.jp/books?id=wQN7ucw5r7gC&lpg=PA97&ots=wolbl2LcL9&dq=top%20bottom%20left%20right%20usg%20images&hl=en&pg=PA113#v=onepage&q&f=false

Fetal Development and Estimated Fetal Weight

http://www.jsog.or.jp/PDF/59/5906-168.pdf

Online Medical Dictionary

http://lsd.pharm.kyoto-u.ac.jp/en/service/weblsd/index.html