If you look at this page http://msdn.microsoft.com/en-us/library/ms189499 What does the [,...n] mean? I have my suspicions that it's just Microsoft's alternative to using the sequence { } symbols.
That nice big link right above the Syntax block on those MSDN pages lays out their "conventions." For [,...n], it has this to say:
Indicates the preceding item can be repeated n number of times. The occurrences are separated by commas.