APA

Armstrong W Earl, Stinnett T M, . (1957). Manual on certification requirements for school personnel in the United States: Including requirements in the forty-eight states, Alaska, district of columbia, Hawaii, and pureto rico. Washington, USA: National Education Association.

Chicago

Armstrong W Earl, Stinnett T M, . 1957. Manual on certification requirements for school personnel in the United States: Including requirements in the forty-eight states, Alaska, district of columbia, Hawaii, and pureto rico. Washington, USA: National Education Association.

Harvard

Armstrong W Earl, Stinnett T M, . (1957). Manual on certification requirements for school personnel in the United States: Including requirements in the forty-eight states, Alaska, district of columbia, Hawaii, and pureto rico. Washington, USA: National Education Association.

MLA

Armstrong W Earl, Stinnett T M, . Manual on certification requirements for school personnel in the United States: Including requirements in the forty-eight states, Alaska, district of columbia, Hawaii, and pureto rico. Washington, USA: National Education Association. 1957.