1. AASHTO. (2003). The California bearing ratio. Washington, DC: AASHTO T 193-99.
2. AASHTO. (2012). Classification of soils and soil-aggregate mixtures for Highway Construction purposes. Washington, DC: AASHTO M 145-91.
3. AASHTO. (2012). Determining the resilient modulus of soils and aggregate materials. Washington, DC: AASHTO T 307-99.
4. AASHTO. (2012). Moisture-density relations of soils using a 4.54-kg (10-Ib) Rammer and a 457-mm (18-in.) Drop. Washington, DC: AASHTO T 180-97.