Heylen, L. (1865). The progress of the age, and the danger of the age: Two lectures delivered before the St. Xavier Conference of the St. Vincent de Paul Brotherhood in the hall of St. Louis University. J. P. Walsh.

Heylen, Louis. The Progress of the Age, and the Danger of the Age: Two Lectures Delivered Before the St. Xavier Conference of the St. Vincent De Paul Brotherhood in the Hall of St. Louis University. Cincinnati: J. P. Walsh, 1865.

Heylen, Louis. The Progress of the Age, and the Danger of the Age: Two Lectures Delivered Before the St. Xavier Conference of the St. Vincent De Paul Brotherhood in the Hall of St. Louis University. J. P. Walsh, 1865.