9Matthew J.Hannon,Timothy J.Foxon,William F.Gale.“Demand pull”government policies to support Product-Service System activity:the case of Energy Service Companies(ESCos)in the UK[J].Journal of Cleaner Production,2015(5):1-16.
10Jakob Edler,Luke Georghiou.Public procurement and innovation-Resurrecting the demand side[J].Research Policy,2007,36(9):949-963.