Your right the references were a bit lacking. I added the url to the Casey Family Programs fact sheet on PTSD, deleted the one to the Seattle Times article and moved the one for Dubner and Motta.
The fact that PTSD was found to effect 25% of foster children has fairly profound implications for society in general. There are over 500,000 kids in foster care in the United States right now, that's 125,000 cases right there, and PTSD has been shown to have an epigenetic effect, so it affects generations. Yehuda R, Bierer LM. Prog Brain Res. 2008;167:121-35. Transgenerational transmission of cortisol and PTSD risk. PMID 18037011