Tranfaglia, A., & Tremblay, E. 1982 A morphological comparison between Planococcus citri (Ris.), Planococcus ficus (Sign.) and their F1 hybrids (Homoptera: Coccoidea: Pseudococcidae).. Entomotaxonomia 4: 1-5.

Notes: Detailed study on crosses between two sympatric and related species.