APA

United States, . (1973). Proposed reservation system in selected national parks: hearing before Subcommittee on Parks and Recreation, 93d Congress, 1st session, Feb. 23, 1973. [Washington, D.C.]: .

Chicago

United States, . 1973. Proposed reservation system in selected national parks: hearing before Subcommittee on Parks and Recreation, 93d Congress, 1st session, Feb. 23, 1973. [Washington, D.C.]: .

Harvard

United States, . (1973). Proposed reservation system in selected national parks: hearing before Subcommittee on Parks and Recreation, 93d Congress, 1st session, Feb. 23, 1973. [Washington, D.C.]: .

MLA

United States, . Proposed reservation system in selected national parks: hearing before Subcommittee on Parks and Recreation, 93d Congress, 1st session, Feb. 23, 1973. [Washington, D.C.]: . 1973.