Guidance 17

Manual on Government Deficit and Debt, Implementation of ESA95
European Communities (2010 edition)

Part IV (Leases, licences and concessions) covers the treatment of long-term contracts between government units and non-government partners.

http://epp.eurostat.ec.europa.eu/cache/ITY_OFFPUB/KS-RA-09-017/EN/KS-RA-09-017-EN.PDF