1. Abrantes R (1997) Dog language. Wakan Tanka, Naperville
2. Altmann J (1974) Observational study of behaviour: sampling methods. Behaviour 49:227–267
3. Beck AM (1973) The ecology of stray dogs: a study of free-ranging urban animals. York Press, Baltimore, MD, p 98
4. Beck AM (1975) The ecology of feral and free-roving dogs in Baltimore. In: Fox MW (ed) The wild Canids: their systematics, behavioural ecology and evolution. Van Nostrand-Reinhold, New York, pp 380–390
5. Bekoff M (1979) Scent-marking by free-ranging domestic dogs. Biol Behav 4:123–139