I would think that H. Peter Anvin's Device list should be considered the
definitive source of information -- it is maintained, and distributed
as part of the kernel source. Note that this contains:
block SCSI CD-ROM devices
0 = /dev/sr0 First SCSI CD-ROM
1 = /dev/sr1 Second SCSI CD-ROM
...
The prefix /dev/scd instead of /dev/sr has been used
as well, and might make more sense.
So, as far as that is concerned, the device is srX.
Indeed. That was one of the first references I consulted too.
Leonard