1. Relationship between aggressive and avoidance behaviour by dogs and their experience in the first six months of life;Appleby D.L.;Veterinary Record,2002
2. Appleby, D., Sandbacka-Saxén, S., Jokinen, O., Burgherr, T. and Valros, A. (2013) Homing age influences the prevalence of problematic adult canine behaviour. In: Proceedings of the 9th International Veterinary Behavioural Meeting, Lisbon, Portugal, pp. 69–70.
3. Behavior development in the dog: an interspecific analysis;Cairns R.B.;Science,1967
4. Dunbar, I. (2004) Before and After Getting Your Puppy. New World Library, Novato, California.
5. The development of emotional distress reactions to separation in puppies;Elliot O.;Journal of Genetic Psychology,1961