Patents

A patent is "a certificate of grant by a government of an exclusive right with respect to an invention for a limited period of time" (AccessScience Encyclopedia).  Patents can be invaluable sources of information, but are not easy to search for and use.

Standards

Standards are officially approved specifications that cover such topics as methods of testing, terminology, performance, and construction requirements. Often they are not more than a few pages long.  Many bodies issue standards (national and international standards organizations, trade associations, government departments, etc).