中国科学技术信息研究所--国家工程技术数字图书馆

walden university.(10)

michigan state university.(7)

colorado state university.(6)

the university of wisconsin - madison.(6)

utah state university.(6)

arizona state university.(5)

oklahoma state university.(5)

state university of new york college of environmental science and forestry.(5)

capella university.(4)

east carolina university.(4)

north carolina state university.(4)

the university of arizona.(4)

university of arkansas.(4)

university of minnesota.(4)

university of south carolina.(4)

duke university.(3)

old dominion university.(3)

the george washington university.(3)

the university of alabama.(3)

university of maryland college park.(3)

university of ottawa (canada).(3)

university of washington.(3)

capella university(2)

clemson university.(2)

cornell university(2)

cornell university.(2)

george mason university.(2)

harvard university.(2)

howard university.(2)

indiana university.(2)