Ackerman, J.L., et al.: The decision-making process in orthodontics, edited by Graber, L.W., Orthodontics. Current principles and techniques, 5th ed., 39, Elsevier, Phila., 2012.
Proffit, W.R.: The etiology of orthodontic problems, edited by Proffit, W.R., et al., Contemporary orthodontics, 5th edition, 114-446, ELSEVIER, St. Louis, 2012.