CALSpair format alternatives

Hello,

I would like to have more details about how <area> graphic coords calspair  
units should be interpreted, and what are the valid formats.

In the TDG, only the format "x1,y1, x2,y2" is given (in area element  
description), but I guess it is not the only one valid if you look at the  
mediaobjectco, where the format is "x y".

So, are those formats all valid?
- "x1,y1 x2,y2"
- "x y"
- "x1,y1" (if it is valid is it equivalent to "x1 y1"?)

Is there any other valid alternatives?

Thanks,

Regards,
BG