1. Vibration of Stepped Beams
2. Temple, G., and Bickley, W. G., Rayleigh's Principle and Its Application to Engineering, pp.87-103; Dover Publications, New York, 1956.
3. Crandall, S. H., Engineering Analysis, pp.305-306; McGraw-Hill Book Co., Inc., New York, 1956.
4. Collatz, L., Eigenwertprobleme und Ihre numerische Behandlung, pp.177-186; Chelsea Publishing Co., New York, 1948.