Empirical Studies
Secure Phylogenetic Attachment, Dyadic Trauma, and Completion Across the Life Cycle
Joseph P. Riordan, Abi Blakeslee, and Peter A. Levine

Research
The Somatic Experiencing Trauma Institute has published some interesting research related to Somatic Experiencing.

Working with trauma is as much about remembering how one survived as it is about what is broken.
Bessel van der Kolk