United States National Arboretum contribution
U.S. Dept. of Agriculture, Agricultural Research Service
by Frederick G. Meyer, Peter M. Mazzeo, and Donald H. Voss
U.S. Dept. of Agriculture, Agricultural Research Services 1994 United States National Arboretum contribution no. 7
Available at 3 libraries
by Roland M. Jefferson and Alan E. Fusonie
Agricultural Research Service, U.S. Dept. of Agriculture 1977 United States National Arboretum contribution no. 4
Available at 10 libraries