John, O. 1930 Material zur Insektenfauna Lettlands: 1. Zur Coccidenfauna Lettlands.. Folia Zoologica et Hydrobiologica 2: 3-7.

Notes: Species mentioned include Chrysomphalus dictyospermi, Aspidiotus hederae, A. abietis, Lepidosaphes ulmi, Chionaspis salicis and Pinnaspis aspidistrae.