Search Results Use the search box below to revise your search, or start a new search. Studies (1) Variables Publications Your query returned 1 studies. Series results are grouped under the most relevant study. Ungroup series results to view all results. Sort by: Title A-Z Released/Updated Time Period Most Cited in ICPSR Bib. 1. Sociological Study of Backcountry Users at Grand Canyon National Park, 1984-1985 (ICPSR 8543) Underhill, A. Heaton; Stewart, William P.; Manning, Robert E.; et al.