mine!

[Ann Dowker]

Although the following papers deal only in part with possessives,
they may be relevant:

Charney, R. (1980). Speech roles and the development of personal
pronouns. Journal of Child Language, 7, 509-528.

Loveland, K.A. (1984). Learning about points of view: spatial
perspective and the acquisition of "I/you". Journal of Child Language,
11, 535-556.

Both papers deal mainly with 2-year-olds. According to the Loveland
paper, the consensus seems to be that both personal pronouns and personal
possessive terms are used correctly before age 3, but performance can
vary greatly according to the social context and other cognitive (e.g.
spatial) demands of the task.

Ann