Cochran, K. / 1993 / Pedagogical content knowing-an integrative model for teacher preparation / Journal of Teacher Education 44 : 263 ~ 272 Croft, L. J. / 2003 / Teachers of the gifted: Gifted teachers, In Handbook of gifted education / Allyn & Bacon : 558 ~ 571 Hansen, J. B. / 1994 / Comparison of trained and untrained teachers of gifted students / Gifted Child quarterly 38 (3) : 115 ~ 123 Landrum, M. S. / 2001 / Professional development, In Aiming for excellence: Annotations to the NAGC pre-K-grade 12 gifted program standards / Prufrock Press Inc Magnusson, S. / 1999 / Nature, Sources and development of pedagogical content knowledge, In Examining pedagogical content knowledge / Kluwer Academic Publishers : 95 ~ 132