中国科学技术信息研究所--国家工程技术数字图书馆

colorado state university.(9)

harvard university.(8)

arizona state university.(7)

university of washington.(7)

rutgers the state university of new jersey - new brunswick.(6)

michigan state university.(5)

university of minnesota.(5)

university of toronto (canada).(5)

iowa state university.(4)

the university of north carolina at chapel hill.(4)

university of california los angeles.(4)

university of colorado at boulder.(4)

university of maryland college park.(4)

university of south florida.(4)

walden university.(4)

capella university.(3)

southern university and agricultural and mechanical college.(3)

state university of new york college of environmental science and forestry.(3)

texas a&m university.(3)

the florida state university.(3)

the ohio state university.(3)

tufts university.(3)

university of california irvine.(3)

university of georgia.(3)

university of hawai'i at manoa.(3)

villanova university.(3)

wayne state university.(3)

capella university(2)

clemson university.(2)

drexel university.(2)