Acoustical Standards
Acoustical Society of America

BAE Systems (USA)
Technical reference development and research data concerning acoustical imaging.

How Stuff Works: How Ultrasound Works
Illustrated narrative takes you inside the ultrasound machine and shows you how this technique is used to look inside you.

NDT-net (Rolf Diederichs)
UT-Encyclopedia

Nondestructive Material Testing with Ultrasonics
Introduction to the Basic Principles (Krautkrämer, NDt-net)

Nondestructive Testing Information Analysis Center (NTIAC)
NTIAC is a Defense Technical Information Center (DTIC) funded, Department of Defense (DoD) Information Analysis Center operated by Texas Research Institute Austin, Inc.

Super High Resolution Ultrasonic Measurement System
5-micro-meter resolution measurement by non contact system in the air; RS-232 interface; Thickness, Deviation, Distance, Level of any kind of material.

Ultrasonics
IEEE Web Thesaurus - Keywords

Ultrasonics
Dedicated to the art and science of ultrasonic nondestructive testing and allied fields.

Vibrationdata.com Tutorials
The tutorials and course materials require a username and password which can be obtained with an annual subscription fee.