1. Felix Helié Traité de balistique expérimentale , Dumaine, Paris 1840
2. N. A. Tolch Ballistic Research Laboratories, Aberdeen Proving Ground, Aberdeen, Maryland
3. Some Observations on High-Speed Impact*
4. Ernest Öpik Researches on the Physical Theory of Meteor Phenomena: I. Theory of the Formation of Meteor Craters Acta et Comm. Univ. Tartuensis 1936