Open University
发表
A. R. King,
K. Schenker,
U. Kolb,
2000
.
Open University,
UK,
France,
2003
.
P. S. Conti,
Open University,
R. D. Blum,
2008,
0803.3853.
David Hall,
Open University,
Holger Israel,
2014,
1401.1151.
Open University,
UK,
France,
2004
.