rdfs:comment (described at http://www.w3.org/TR/2009/WD-owl2-new, form of an HTTP Uniform Resource Locator (URL), to, by using CiTO object properties, e.g. http@en
rdfs:comment bibliographic information, for example PubMed (http, Search (http://search.crossref.org/) and PubMed, Central (http://www.ncbi.nlm.nih.gov/pmc/). @en