Ultrasound - Definition from encyclopedia.com

NDT-net (Rolf Diederichs) - UT-Encyclopedia

Ultrasonics - What is it ? - Created by Students for ThinkQuest

Nondestructive Testing Newsgroup - The newsgroup sci.techniques.testing.nondestructive is dedicated to the exchange of information and discussion of issues relating to nondestructive testing of materials and structures.

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

Acoustics FAQ - An informal file of typical questions and answers on acoustical topics. Campanella Associates

Ultrasonics - IEEE Web Thesaurus - Keywords

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

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

NDT.org - A nondestructive testing online community.

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.

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.

Acoustical Standards - Acoustical Society of America

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

Acoustic Cavitation - TU Darmstadt (Germany)

Piezo Solutions - an Engineering and Manufacturing Consulting Service which assists companies who manufacture and utilize piezoelectric ceramic elements in their products to improve performance, yield, quality and reliability.

Glossary of Transducer Terms - ITC

Definitions of Ultrasonic Instrument Parameters - ndt.net