If you are citing multiple works by the same author from a collection that includes contributions by other authors, create a works-cited-list entry for each work you are citing: 

Works Cited

Milton, John. Areopagitica. The Norton Anthology of English Literature, edited by E. Talbot Donaldson et al., 4th ed., vol. 1, W. W. Norton, 1979, pp. 1399-1409. 

———. Samson Agonistes. The Norton Anthology of English Literature, edited by E. Talbot Donaldson et al., 4th ed., vol. 1, W. W. Norton, 1979, pp. 1540-83. 

You may also provide a main entry for the collection and create cross-references to it:

Works Cited

Donaldson, E. Talbot, et al., editors. The Norton Anthology of English Literature, 4th ed., vol. 1, W. W. Norton, 1979. 

Milton, John. Areopagitica. Donaldson et al., pp. 1399-1409.

———. Samson Agonistes. Donaldson et al., pp. 1540-83.

If you are citing multiple works by the same author and using a single collection of that author’s works—edited or not—then you may generally cite the collection as a whole in your works-cited list and refer to the individual works in your text:

Whereas in Areopagitica Milton praises those who would “advance the publick good” by publishing their thoughts (997), in Samson Agonistes he constructs a much more complicated portrait of a man whose worthy actions proceed from “intimate impulse” unknown to others (line 223).

Work Cited

Milton, John. The Riverside Milton. Edited by Roy Flanagan, Houghton Mifflin, 1998.

If, however, you cite just one work from the collection, you could create an entry for it in your works-cited list:

Milton’s Areopagitica is an eloquent plea for citizens to join in a common cause to “unite those dissever’d peeces which are yet wanting to the body of Truth” (1018). 

Work Cited

Milton, John. Areopagitica. The Riverside Milton, edited by Roy Flanagan, Houghton Mifflin, 1998, pp. 987-1024.