Our Intelligent Companions, the Plants:  .

Chapter Six- Cleve Backster's Laboratory: - A chapter in a web-based book by psychologist Ingo Swann. Deals with a trip made by Swann to Backster's laboratory and chronicles the first-hand experiment he witnessed.

Dark Corner - Plants Feel: - Offers information on how plants can read human minds.

Plant Articles by Judith Handelsman: - A series of articles from various magazines. The second one has relevance primary perception discoveries, as it describes Handelsman's own experiences with the phenomenon.

Vignettes From the History of Plant Morphology: - Articles about people, mostly Agnes Arber, who created unconventional theories about plant morphology.

Subtle Energy: - An article in a web-based magazine by Paul von Ward Lightworks. Deals with Cleve Backster's mind-plant discoveries and the author's speculations about them. (May 5, 1998)