>
>There is a discussion of both systems here:
>
>http://www.sunderland.ac.uk/~os0dwe/bs12.html
>

Interesting and helpful link. Cone's system seems to be a hybrid
between the CPD system and the old PED system, since she uses Dhp for
Dhammapada (like CPD) but M for Majjhimanikaaya (like PED).

Since the CPD project has been stalled for a long, long time, I would
be inclined to go with Cone's conventions as superceding CPD.