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.

National Center for Appropriate Technology. ATTRA - National Sustainable Agriculture Information Service.

"Permaculture is about designing ecological human habitats and food production systems. This publication discusses permaculture concepts and applications, and offers listings of resource organizations and references on permaculture."