| » 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. |
| » 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) |