There are two kinds of string art, the kind done with nails and the kind done with holes in the medium.
I prefer the type with holes.
Nail String Art
Hole String Art
- String Art Symmography: Three-Dimensional Creative Designs with Yarn without Knotting or Kniting, by Lois Kreischer. 1971
- Symmography: Linear Thread Design, by Laura Sarff and Jan Harem, 1979
- String Art: Step By Step, by Robert E. Sharpton, 1975
There are many more books, and information on the Internet, including Youtube.