Currently there are two ways in use to list series of "op." works for artists.

First problem, series naming:
The first and most common way is to call it "John Doe's Opus".
The other is "John Doe opera".

Second problem, opus numbering:
The most common way is to number it "op. #"
The other is to have the number be simply "#".

It would be nice if this were consistent across the board.