On PPP's there is quite some theoretical literature. - e.g.
Bovaird, Tony. 2004. "Public–Private Partnerships: from Contested Concepts to Prevalent Practice." International Review of Administrative Sciences 70 (2):199-215. doi: 10.1177/0020852304044250.
Klievink, Bram. 2011. Unravelling Interdependence: Coordinating Public-Private Service Networks: Delft: Delft University of Technology.
Klievink, Bram, and Marijn Janssen. 2012. "Challenges in Developing Public-private Business Models." European Journal of ePractice 18 (2012).
On the practicality of PPP's I like the figure on the website: http://www.pppcouncil.ca/resources/about-ppp/models.html
In my interpretation it shows essentially that parties collaborating in PPP's tend to optimize on risk / accountability avoidance and on public value (besides cost savings - although that is still disputed - are PPP's realy cheaper for the tax payer at the end?).
PPPs are typically principal-agent relationships, so that, rather than a single optimization, there may be several (at least two ) optimizations going one at once. The real problem is thus to find a contract structure with optimal characteristics, in the sense that it serves best the collective welfare through an appropriate structure of incentives for the two parties. I used this approach in the attached paper on concessions, which also looks at the added complication of risk sharing, itself a key characteristic of PPPs. .