Gaya APA

Checkley., K. (2006). The essentials of mathematics, grades 7–12 : effective curriculum, instruction, and assessment . Virginia: Association for Supervision and Curriculum Development.

Gaya MLA

Checkley., Kathy. "The essentials of mathematics, grades 7–12 : effective curriculum, instruction, and assessment". Virginia: Association for Supervision and Curriculum Development, 2006. Electronic Resource.