Issue: A standard mechanism for "links" or "cross references" is very
desirable for things like combining images and sounds into animations.
Perhaps we'll define "link" chunk within forms that refer to other forms
or to specific chunks within the same and other FORMs.  This needs further
work. EA IFF 1985 has no standard link mechanism.

For now, it may suffice to read a list of, say, musical instruments, and
then just refer to them within a musical score by  sequence  number.