1. Beer CG (1982) Conceptual issues in the study of communication. In: Kroodsma DE, Miller EH (eds) Acoustic communication in birds. Vol 2, Academic Press, New York, pp 279?310
2. Busnel R-G (1968) Acoustic communication. In: Sebeok TA (ed) Animal communication. Indiana University Press, Bloomington, IN, pp 127?153
3. Catchpole CK (1983) Variation in the song of the great reed warbler Acrocephalus arundinaceua in relation to mate attraction and territorial defence. Anim Behav 31:1217?1225
4. Falls JB (1982) Individual recognition by sounds in birds. In: Kroodsma DE, Miller EH (eds) Acoustic comminication in birds. Vol 2, Academic Press, New York, pp 237?277
5. Falls JB, Krebs JR, McGregor PK (1982) Song matching in the Great Tit (Parus major); The effect of similarity and familiarity. Anim Behav 30:997?1009