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ContributorsMcCarl, J. R. (Author)
Created1927-11-15
Description

Letter from J. R. McCarl to Secretary of the Interior on concessions and contracts in the park.

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Created1986-04
Description

Cooperative National Park Resources Studies Unit for University of Arizona, effects on Glen Canyon Dam releases on Grand Canyon River trips, a technical report, vol. no. 16.

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Created1986-03
DescriptionCooperative National Park Resources Study Unit of Arizona, a special report, v no. 4, improving viistor communciation in Grand Canyon National Park