Website address for webcomics and web magazines is needed.
For example: http://www.mangaupdates.com/publishers.html?pubname=Beat%27s is a webcomic magazine http://comic.mag-garden.co.jp/beats/ You can read all comics online, legally.

As far as I know, it's fine to put the address of a web comic series in the description. We don't keep any details about magazines though (besides what series have run in it), so there's nowhere to put the address for them. But having the address for the individual series should be enough anyway, I think.

Manga Cover Database