Sheffield, L. J. (2003). Extending the challenge in mathematics: Developing mathematical promise in K-8 students. Corwin Press.
Chicago-viite (17. p.)Sheffield, Linda Jensen. Extending the Challenge in Mathematics: Developing Mathematical Promise in K-8 Students. Thousand Oaks, CA: Corwin Press, 2003.
MLA-viite (8. p.)Sheffield, Linda Jensen. Extending the Challenge in Mathematics: Developing Mathematical Promise in K-8 Students. Corwin Press, 2003.
Varoitus: Nämä viitteet eivät aina ole täysin luotettavia.