Gosler, A., Gosler, A., & Perrins, C. (1987). Some aspects of bill morphology in relation to ecology in the great tit Parus major.

Gosler, A., Andrew Gosler, and C. Perrins. Some Aspects of Bill Morphology in Relation to Ecology in the Great Tit Parus Major. 1987.

Gosler, A., et al. Some Aspects of Bill Morphology in Relation to Ecology in the Great Tit Parus Major. 1987.