@Article{366741,
     author = "Arleta Suwalska",
     title = "The principles of non-formal, free education on the examples of schools described by David Gribble in Worlds Apart and Lifelines",
     year =  2013,
     volume =  4,
     number =  1 (6),
     journal =  Studia z Teorii Wychowania,
     pages =  s. 191-201,
    }