This research article from the Journal of Clinical Child Psychology (Vol 28, No. 1, 1999) looks at young children's social skills, including problem solving, self-perception and the perception of others.
Part 1: Reactive aggression
This article by Dan Gartrell (March 2011) is the first in a two-part series about helping children who have serious conflicts - how to build and maintain positive relationships with every child, even during conflicts.
In this reserach, Thornberg considers the strategie that young children use when engaged in conflict. The link provided downloads a pdf report of the research.
Robert Thornberg, The Situated Nature of Preschool Children's Conflict Strategies, 2006, Educational Psychology, (26), 1, 109-126.