1. Alvarez, A.E., W.F. Tjallingii, E. Garzo, V. Vleeshouwers, M. Dicke, and B. Vosman. 2006. Location of resistance factors in the leaves of potato and wild tuber-bearing Solanum species to the aphid Myzus persicae. Entomologia Experimentalis et Apllicata 121(2): 145–157.
2. Davis, J.A. 1971. Elementary survey analyses, 325. Englewood cliffs: Prentice-Hall.
3. Gibson, R.W., and R.T. Plumb. 1977. Breeding plants for resistance to aphid infestation. In Aphids as virus vectors, ed. K.F. Harris and K. Maramorosch, 473–500. London: Academic.
4. Gopal, J., V. Kumar, and S.K. Sandhu. 2003. Biosystematics and genetic resources of potato. In The potato: production and utilization in sub-tropics, ed. S.M.P. Khurana, P.S. Naik, J.S. Minhas, and S.K. Pandey, 31–47. New Delhi: Mehta Publishers.
5. Green, S.B., N.J. Salkind, and T.M. Akey. 2000. Using SPSS for windows: analyzing and understanding data, 2nd ed. USA: Prentice Hall.