“Morphology of Cysts and Second Stage Juveniles of Heterodera Filipjevi (Madzhidov, 1981) Stelter, 1984 from Norway”. Journal of Nematode Morphology and Systematics, vol. 7, no. 1, Nov. 2009, pp. J. Nem. Morph. Syst., 7 (1): 77-84 (2004), https://revistaselectronicas.ujaen.es/index.php/jnms/article/view/103.