North Carolina State University Extension Service.

This overview of permaculture discusses design skills and permaculture prinicples.

Permaculture Institute.

Articles, videos, and other resources about permaculture in various settings and applications.

Utah State University. Extension and Agriculture.

This article highlights "the theoretical and applied elements of permaculture." The author defines permaculture, discusses permaculture theory and practices, and describes twelve "ethics and principles" of permaculture.  Includes glossary.