What I'd like to do is to cite classical works. For example, to cite Aristotle's Metaphyisic according to the Bekker's cannonical edition. How could I do this using biblatex with author-year style?
In my experience citing medieval and classical texts, the most flexible approach --- given that different journals and publishers have different rules about citing pre-modern works --- is to create your own citation commands for these works. Biblatex is extremely flexible, but unless you are sure one shorthand will work for everything you'll ever write, it can't do the job unless you (re-)create a .bib entry for each paper or book.
For a basic paper, what I do is something like the following, given the following .bib entry:
(Note, I treat modern editions of works as being 'authored' by the modern editor of the work since our 'critical' editions of these works are but reconstructions of what the medieval or classical author wrote. Not everyone agrees with this view, so you may want to add Aristotle in the author field.)
Now, create a custom citation command:
gives you: 'Met. 1048a36' along with an invisible citation of the Ross edition and a command to manually re-set
Or be more complicated. Imagine you wanted to provide a parenthetical reference to the page number(s) of Ross's edition:
Obviously, more fancy versions are possible, but think carefully about what you want: will a reference to long sections of the text be required (e.g., Met. 1067b1--1068a7)? do you want to include book and chapter information (e.g., Met. 11.11.1067b1--1068a7)? do you want the references to the 'a' and 'b' columns to be superscript? Etc., etc.
One final thought. If this is a longer project, and you plan on something like an index locorum, make sure you create the commands in such a way that you can extract the relevant information consistently from these commands. That is, if you want to provide more detailed information in the ntoes of your text than will appear in the index, make sure you break down the discrete parts of the citation into different mandatory arguments (using, say, something like
To cite a classic, you can use
You may use the
And this is how to use it with