1. Three-Arc Vertical Curve for Constrained Highway Alignments
2. Easa S. M. Abd El Halim A. O. and Hassan Y. (1996). “Sight distance evaluation on complex highway vertical alignments.” Can. J. Civ. Engrg. Ottawa 23 577–586.
3. Functional requirements of highway safety features. (1983). Fed. Hwy. Admin. U.S. Department of Transportation Washington D.C.
4. A guide for selecting locating and designing traffic barriers. (1977). American Association of State Highway and Transportation Officials Washington D.C.
5. Hassan Y. Easa S. M. and Abd El Halim A. O. (1995). “Sight distance on horizontal alignments with continuous lateral obstructions.” Transp. Res. Rec. 1500 Transportation Research Board Washington D.C. 31–42.