Incoming Resources
- NGHT, Washington, D.C.?, 2009
- U.S. Dept. of Education, Office of Education Research and Improvement, Washington, D.C.?, 1993
- U.S. Dept. of Education, Office of Educational Research and Improvement, Washington, D.C.?, 1993
- National Geographic Video, distributed by Vestron Video, Washington, D.C.?, Stamford, CT, c2010
- National Geographic, Washington, D.C.?, c2009