References
- Brown , Vinson . 1972 . Reading the outdoors at night , Harrisburg , Pennsylvania : Stackpole Books .
- Buell , Larry . 1983 . The 24-hour experience , Greenfield , Massachusetts : Environmental Awareness Publications .
- Martin , Alexander C. , Zim , Herbert S. and Nelson , Arnold L. 1951 . American wildlife and plants , New York : Dover Publications, Inc .
- Sisson , Edith A. 1982 . Nature with children of all ages , Englewood Cliffs , New Jersey : Prentice-Hall, Inc .
- Zim , Herbert S. and Baker , Robert H. 1975 . Stars , New York : Golden Press .