Παραπομπή APA

(1967). Pennsylvania's regions: A survey of the Commonwealth. Harrisburg: Pennsylvania State Planning Board.

Παραπομπή Chicago Style

Pennsylvania's Regions: A Survey of the Commonwealth. Harrisburg: Pennsylvania State Planning Board, 1967.

Παραπομπή MLA

Pennsylvania's Regions: A Survey of the Commonwealth. Harrisburg: Pennsylvania State Planning Board, 1967.

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