@article {Perez1990,
	title = {Modeling daylight availability and irradiance components from direct and global irradiance},
	journal = {Solar Energy},
	volume = {44},
	number = {5},
	year = {1990},
	note = {<br />},
	pages = {271 - 289},
	issn = {0038-092X},
	doi = {DOI: 10.1016/0038-092X(90)90055-H},
	url = {http://www.sciencedirect.com/science/article/B6V50-497T9KG-S0/2/034fdf1417cea3a44d8509fe805f679e},
	author = {Richard Perez and Pierre Ineichen and Robert Seals and Joseph Michalsky and Ronald Stewart}
}
