Physical description for original version: 35 p. : 28 cm
書誌注記
Includes bibliographical references (p. 24)
原資料等に関する注記
原資料の出版事項: St. Paul, Minn. (1992 Folwell Ave., St. Paul 55108) : U.S. Dept. of Agriculture, Forest Service, North Central Forest Experiment Station, 1990