The two-year study of sustainability at a regional scale – comparing the Randstad with the South East of England – was completed in 2011 with results published in a new publication . The report brings together the findings of an interdisciplinary collaboration between ÐÓ°ÉÂÛ̳ Cities, the Dutch Ministry of Infrastructure and the Environment and the Netherlands Environmental Assessment Agency. The research presents thinking on what makes strong regional cities, identifying a number of key factors to consider: regional and intra-regional relationships; agglomeration economies; access for city dwellers to green space; and the hubs and hotspots of the wider urban networks. The report was submitted to the Dutch government at a formal presentation in The Hague on 1 September 2011.