5Liu, B. Y. H. and Jordan, J. C. Daily Isolation on Surfaces Tilted Towards the Equator [ J] , Trans. ASHRAE, 1962:526-541.
6Klein, S. A. Calculation of Monthly Average Insolation on Tilted Surfaces [J] , Solar Energy, 1977, 19 : 325-329.
7Klien, S. A., Theilacker, J. C. An algorithm for calculating monthly-average radiation on inclined surface [J] . Journal of Solar Energy Engineering, 1981, 103: 29-33.
8Erba, D. G., Duffle, J. A. Estimation of diffuse radiation fraction for hourly, daily and monthly average global radiation [J] . Solar Energy, 1982, 28 (4): 293- 304.
8Gopinathan K K. Solar radiation on variously oriented sloping surfaces[J]. Solar Energy, 1991, 47(3): 173--179.
9Yakup M A H, Malik A Q. Optimum tilt angle and orientation for solar collector in Brunei Darussalam[ J ]. Renewable Energy, 2001, 24: 2231234.
10Koronakis P S. On the choice of the angle of tilt for south facing solar collectors in the Athens Basin area[J]. Solar Energy, 1986, 36(3): 217--225.