Name Info Provider Link
subscription/membership/fee required Ovid Technologies, Inc. http://ovidsp.ovid.com/ovidweb.cgi?T=JS&PAGE=linkout&SEARCH=17559693.ui
free resource PubMed Central https://www.ncbi.nlm.nih.gov/pmc/articles/pmid/17559693/
subscription/membership/fee required Cambridge University Press https://www.cambridge.org/core/product/identifier/S0950268807008783/type/journal_article