Sinclair, A. R. E., Krebs, C. J., Fryxell, J. M., Turkington, R., Boutin, S., Boonstra, R., Seccombe-Hett, P., Lundberg, P., and Oksanen, L., 2000, Testing hypotheses of trophic level interactions: a boreal forest ecosystem: Oikos, v. 89, no. 2, p. 313-328.