- Design Manual. Washington State Department of Transportation [on-line], USA, 2017, https://www.wsdot.wa.gov/publications/manuals/fulltext/M22-01/design.pdf
- The Design Manual for Roads and Bridges [on-line]. The Highways Agency, Department for Transport, United Kingdom, http://www.dft.gov.uk/ha/standards/dmrb/
- According to the recommendations of teachers with regard to the specific project assignment.