References
- Longley , P. A. , Goodchild , M. F. , Maguire , D. J. and Rhind , D. W. 2005 . Geographic Information Systems and Science , Chichester : John Wiley and Sons .
- Mitchell , A. 2005 . The ESRI Guide to GIS Analysis , Volume 2 , Redlands : ESRI Press .
- NORWEGIAN MINISTRY OF TRANSPORT AND COMMUNICATIONS . 2009 . National Transport Plan 2010–2019 , Oslo : Norwegian Ministry of Transport and Communications . Norwegian White Paper No. 16 (2008–2009)
- Silverman , B. W. 1986 . Density Estimation for Statistics and Data Analysis , New York : Chapman and Hall .