According to the MHRA Style Guide, this item should be cited in a bibliography as follows:

Green, Toby, and Malyn Newitt (eds), Formal and Informal Empire: Portuguese Relations with the Non-European World (= Portuguese Studies, 28.2 (2012))

This is how standard MHRA style would look. Some of its book series (notably Legenda) allow an alternative citation system called 'author-date', but please talk to your editor before using it. (To see the demonstration for author-date, follow this link.)

Let's take this bibliography entry one step at a time:

Step 1. The entry begins with the author(s) or editor(s) of the volume, with the first name inverted into Surname, Forename. This is because a Bibliography is a list in surname order, so we need a surname up front.

Green, Toby, and Malyn Newitt

Step 2. If somebody has a role other than that of author, it goes next, in brackets. One editor becomes '(ed.)', two or more '(eds)'. (Remember: 'ed.' stands for 'editor', not 'edited', so the full stop must be used, because 'd' is not its last letter.)

Green, Toby, and Malyn Newitt (eds)

Step 3. Now a comma, not a full stop:

Green, Toby, and Malyn Newitt (eds),

Step 4. This is a themed and titled journal issue, so we give that title here, just as if it were a book.

Green, Toby, and Malyn Newitt (eds), Formal and Informal Empire: Portuguese Relations with the Non-European World

Step 5. We gave this a title as if it were a book, but we need to give the equivalent journal citation as well: note the '=' sign.

Green, Toby, and Malyn Newitt (eds), Formal and Informal Empire: Portuguese Relations with the Non-European World (= Portuguese Studies, 28.2 (2012))

And that's the finished bibliography entry. Note that there's no final full stop.

So how about citations in footnotes or endnotes?

In standard MHRA style, the first time the work is cited in a note, it should be cited in full. This looks very like a Bibliography entry, but:

• The author's name doesn't always come first: only for monographs. For collections and editions, the title comes first.
• Even if the author's name does come first, it's back to being the right way round, so it's Forename Surname, not Surname, Forename;
• Unlike Bibliography entries, notes are punctuated as sentences, and usually end in full stops.

Suppose we want to cite a passage on pages 24 to 27:

³⁴ See Formal and Informal Empire: Portuguese Relations with the Non-European World, ed. by Toby Green and Malyn Newitt (= Portuguese Studies, 28.2 (2012)), pp. 24-27.

But in any subsequent notes, a heavily abbreviated form is used:

³⁷ Compare Green and Newitt, p. 17.