1. A policy on geometric design of highways and streets . (1990). American Assoc. of State Highway and Transp. Officials (AASHTO) Washington D.C.
2. Lateral clearance to vision obstacles on horizontal curves;Easa S. M.;Transp. Res. Record,1991
3. Sight distance model for unsymmetrical crest curves;Easa S. M.;Transp. Res. Record,1991
4. Sight distance models for unsymmetrical sag curves;Easa S. M.;Transp. Res. Record,1991
5. Easa S. M. (1991d). “Highway curves: Geometric and sight distance characteristics.” Report CE‐91‐4 Dept. of Civ. Engrg. Lakehead Univ. Thunder Bay Ontario Canada.