1. Kasasian, L.: PANS 17, 35 (1971)
2. Musselman, L. J.: Ann. Rev. Phytopath. 18, 463 (1980)
3. Pieterse, A. H.: Abs. Trop. Agr. 5, 9 (1979)
4. Pieterse, A. H., Pesch, C. J.: ibid. 9, 9 (1983)
5. Visser, J. H.: South African Parasitic Flowering Plants. Cape Town-Johannesburg: Juta 1981