Gray, D. E. (1961). Identification of user-groups in forest recreation and determination of the characteristics of such groups. [publisher not identified].
Chicago Style (17th ed.) CitationGray, David E. Identification of User-groups in Forest Recreation and Determination of the Characteristics of Such Groups. [Place of publication not identified]: [publisher not identified], 1961.
MLA (9th ed.) CitationGray, David E. Identification of User-groups in Forest Recreation and Determination of the Characteristics of Such Groups. [publisher not identified], 1961.
Warning: These citations may not always be 100% accurate.