What is the proper way of referencing journals, as opposed to papers within journals? I am wondering how to reference a journal (not a paper published in that journal, nor even an edition of that journal). Ought I to give a formal citation or is it enough to name that journal in the text?
The specific example which caused my confusion is the Archive of Formal Proofs (AFP) which is a repository of proofs in Isabelle along with papers describing them. It is not exactly a journal itself, I suppose, but I think it is similar enough that I have generalised this question to ask about 'journals' (it describes itself as 'organized in the way of a scientific journal').
Another option I suppose would be to cite a paper written by the developers of the AFP about the technology used in the AFP, or the organisation of the AFP.
It is probably best that it goes in the bibliography, which should represent a full accounting of the resources you draw on. It is an obvious place to put the URL of the web site.
In general, it is better to be a bit formal in such things than informal, whether you literally need to cite it or not.