Here we have compiled a list of what we hope are useful resources available on or via the internet. These include links to the sites of proprietary software suites and to those providing programs that are shareware, or low cost, or entirely free of license. These sites are in themselves often rich sources of background information and technical help. Second, we include links to online information and technical resources that are largely independent of any allegiance to particular software or are provided by independent (often charitable) organisations. Third, a list of online data sources is provided, some of which allow download of data (either free of charge or with some payment system in place), and others that merely enable browsing of available data as quick looks or listings.
