@conference {17167,
	title = {Enhancement of the Limiting Efficiency of Solar Cells via Bandgap grading},
	booktitle = {11th European Photovoltaic Solar Energy Conference.},
	year = {1992},
	month = {12-16 October 19},
	address = {Montreux, Switzerland},
	author = {S. E.-D. Habib and NADIA H. RAFAT}
}
