Author:Wilbur Samuel Jackman
- Nature Study for Grammar Grades (1899) (external scan)
- "The Relation of School Organization to Instruction" in Popular Science Monthly, 70 (February 1907)
Some or all works by this author were published before January 1, 1928, and are in the public domain worldwide because the author died at least 100 years ago. Translations or editions published later may be copyrighted. Posthumous works may be copyrighted based on how long they have been published in certain countries and areas.