By Orion

Bibliography

http://www.ww2sci-tech.org/lessons/lessons3.html

http://inventors.about.com/od/sstartinventions/a/sonar_history.htm

http://inventors.about.com/od/militaryhistoryinventions/a/Military_Subs_2.htm

http://teacher.scholastic.com/activities/explorations/bats/libraryarticle.asp?ItemID=234&SubjectID=110&categoryID=3

http://www.timetoast.com/timelines/history-of-sonar

http://www.pbs.org/wgbh/nova/lochness/sonar2.html