Knowledge spill-overs”, in particular, are considered critical in explaining the benefits of cities in modem service-oriented economies. However, they do have relatively strong connections to larger urban regions in the form of: good transport links, access to urban services and considerable market interactions, including supply chain linkages, wholesale and retail functions. While these regions have autonomous labour markets, which means that workers do not have ready access to urban jobs, local employers are connected to urban markets. This can provide greater levels of employment and higher wages than would otherwise be the case.