We have subdivided the external links into categories for ease of navigation:
eFunda Huge online engineering reference book, maths, mechanics, physics, ...
e-CFR Daily updated Electronic Code of Federal Regulations for automotive emission testing
UKAS (United Kingdom Accreditation Service) Test Lab Directories
Applegate Manufacturers Directory
Institute of Environmental Sciences and Technology (IEST)
Confederation of European Environmental Engineering Societies (CEEES)
Society of Environmental Engineers (SEE)
GUS Gesellschaft für Umweltsimulation e.V.