Jensen, T. S., Ochsner, P., (1999). Entomologiske Meddelelser 67(2), 47-56. English language
Luik, A., Ochsner, P., Jensen, T. S., (1999). Journal of Applied Entomology 123(9), 561-567. English language
Shea, P. J., (1989). Canadian Entomologist 121(8), 699-708. English language
Shea, P. J., (1989). Oecologia 81(1), 104-110. English language
Hussey, N. W., (1954). Forestry Commission Leaflet.(No. 8), 10 pp. English language