Physical description for original version: iv, 43 p. : 28 cm
書誌注記
Includes bibliographical references (p. 31-34)
原資料等に関する注記
原資料の出版事項: [Reston, Va.?] ; Denver, CO : U.S. Dept. of the Interior, U.S. Geological Survey : For sale by the Books and Open-File Reports Section [distributor], 1991