Often when scraping references from on-line journals, you get the URL field filled in, either with an url or a doi or other refernece number. If this is a print journal (as is normally the case) I don't want the URL/reference to be shown when I output the reference, so I have to go back and delete it either from the reference or from the output. I don't what the solution is - perhaps an on-line journal reference type? But the majority of the time I wouldn't want the contents of the URL displayed for regular journal articles, especially if a doi ref number.