Name Info Provider Link
subscription/membership/fee required Ovid Technologies, Inc. http://ovidsp.ovid.com/ovidweb.cgi?T=JS&PAGE=linkout&SEARCH=7236508.ui
subscription/membership/fee required Wiley https://onlinelibrary.wiley.com/resolve/openurl?genre=article&sid=nlm:pubmed&issn=0007-0963&date=1981&volume=104&issue=4&spage=447
subscription/membership/fee required Silverchair Information Systems https://academic.oup.com/bjd/article-lookup/doi/10.1111/j.1365-2133.1981.tb15316.x