APA

Pharis W. L., National Education Association of the United States, . (1966). In-service education of elementary school principals. Washington: Dept. of Elementary School Principals, National Education Association.

Chicago

Pharis William L, National Education Association of the United States, . 1966. In-service education of elementary school principals. Washington: Dept. of Elementary School Principals, National Education Association.

Harvard

Pharis W. L., National Education Association of the United States, . (1966). In-service education of elementary school principals. Washington: Dept. of Elementary School Principals, National Education Association.

MLA

Pharis William L, National Education Association of the United States, . In-service education of elementary school principals. Washington: Dept. of Elementary School Principals, National Education Association. 1966.