http://www.criticalecho.com/content/icu-echo-tutorials
https://itunes.apple.com/us/itunes-u/uc-irvine-critical-care-ultrasound/id452550953?mt=10
https://itunes.apple.com/us/book/introduction-to-bedside-ultrasound/id554196012?mt=11
http://sonointernist.com/tutorials/
http://www.ultrasoundfirst.org/pages/videos.aspx
http://lifeinthefastlane.com/ultrasound-in-emergency-medicine/
http://www.osuultrasound.com/education/tube--self-study-modules