how do I cite external references so I can have a list of references such as

The answer to the first part of your question is easy:
1. set up a paragraph style, using autonumbering, for the booklist entries

2. use a cross-reference to pull in <$paranum> (plus any formatting you fancy) for a reference to just the number

The answer to the third part is similar: use a cross-reference to pull in <$paranum> and <$paratext> (plus any formatting you fancy) for a full reference to the entry in the booklist

As for the second part, I don't know off-hand. You might be able to do something where you use a table instead of a single style for the booklist entries, then define different styles for each column of the table and set up complex cross-refs to one, two or all three bits of information – but this would be error-prone. See if you can persuade your readers to accept the two easy options.

Post again if you need more information about the details. Oh, and I'd avoid double tabs … even if they didn't look suspiciously like Word ;-}