Bagby, George, Frost and the Book of Nature, Tennessee University Press, 1993, pp. 50-52.

Cox, Robert M, "Robert Frost and the End of the New England Line," in Frost: Centennial Essays, edited by Jac Tharpe, Mississippi University Press, 1974

Ellis, James, "Robert Frost's Four Types of Belief in 'Birches,' " in the Robert Frost Review, 1993, p. 71-3.

Frost, Robert, "The Unmade Word," in Robert Frost: Collected Poems, Prose, & Plays, edited by Richard Poirier and Mark Richardson, Library of America, 1995, p. 697

Hart, Jeffrey, "Frost and Eliot," in Sewanee Review, Vol. 84, No. 3, Summer 1976, pp. 425-47.

Ingebretsen, Ed, "Earth's the Right Place: The Sentence of Love," in Robert Frost's "Star in a Stone Boat": A Grammar of Belief, Catholic Scholars Press, 1994.

Jarrell, Randall, Poetry and the Age, Alfred A. Knopf, 1953.

Kemp, John C., Robert Frost and New England: The Poet as Regionalist, Princeton University Press, 1979.

Lowell, Amy, North of Boston, in New Republic...