Andrachuk, H., et al. (2014). Forest and Nature School in Canada: A Head, Heart, Hands Approach to Outdoor Learning.
MacEachren, Zabe. (2013). The Canadian forest school movement. LEARNing Landscapes, 7, 219-233.
Queen's University professor MacEachren "documents the rationale and benefits of Forest Schools".
Gregory, Alice. (18 May 2017). Running free in Germany's outdoor preschools, New York Times Style Magazine.
Features the Robin Hood Waldkindergarten and notes that a 2003 PhD dissertation by Peter Hafner (Heidelberg) provides evidence that graduates of German forest kindergartens perform "better in cognitive and physical ability, as well as in creativity and social development" than their regular classroom kindergarten peers.
Bringing the Forest School Approach to Your Early Years Practice by 
Forest School and Outdoor Learning in the Early Years by 
Forest School for All by 
International Perspectives on Forest School by 
The Outdoor Classroom Ages 3-7 by 
Risk and Adventure in Early Years Outdoor Play by 