1. Gierhart D. (2011) Personal e-mail communication with Danny Gierhart Asphalt Institute (AI) April 2011.
2. Koo J. H. (2006). "Polymer Nanocomposites - Processing Characterization and Applications " McGraw-Hill Nanoscience and Technology Series ISBN-10: 0071458212.
3. NECEPT (2012). "Superpave System Northeast Center of Excellence for Pavement Technology Northeast Regional Superpave Center " (2012) http://www.superpave.psu.edu/superpave/system.html Last Accessed December 2012.
4. NNI (2013). National Nanotechnology Initiative Online http://www.nano.gov last accessed July 2013.