Mathys, G., & Guignard, E. 1967a Enseignements recueillis au cours de neuf ans de travaux avec Prospaltella perniciosi Tow., parasite du pou de San José Quadraspidiotus perniciosus Comst.. Entomophaga 12(3): 212-222.

Notes: Title in English: [Knowledge collected over nine years of work with Prospaltella perniciosi Tow., parasite of the San José scale Quadraspidiotus perniciosus Cosmt.] The efficacy of Prospaltella perniciosi Tow. as a parasite of Quadraspidiotus perniciosus was tested in 3 climatically different regions of Switzerland with varying degrees of success.