Walczuch, A. 1932 Studien an Coccidensymbioten.. Zeitschrift für Morphologie und Ökologie der Tiere 25: 623-729.

Notes: Describes, discusses, or mentions symbionts for about 33 scale insects representing 19 genera and 5 subfamilies; presents 6 groups of symbionts; discusses these in relation to scale insect classification.