Identify the following type of source.

Isbel, Jason, ed.

Southern Rock Opera.

4 vols.

New York: Harcourt, Brace & World, 1976. Print.

an anthology

books of more than one volume

book by a single author

an edition other than the first edition

This type of source would be

"books of more than one volume"

It appears to be a 4-volume series regarding Southern Rock Opera. We cannot infer that its an anthology, which is a number of collected works within the same genre (such as a 70's rock greatest hits collection), and there are more than one author listed. We also do not know which edition it is.