Pirone, P.P. 1941 . Maintenance of Shade and Ornamental Trees. Oxford University Press New York 422 pp.

Notes: Scales insects mentioned include oyster shell scale, scurfy scale, European elm scale, cottony maple scale, terrapin scale, obscure scale, Lecanium scale, Kermes scale, golden oak scale, tulip scale, San Jose scale, West Indian peach scale, magnolia scale, walnut scale, willow scale, juniper scale, pine leaf scale and spruce bud scale.