1. Adelson-Velskii, G.M., Landis, E.M.: An Algorithm for the Organization of Information. Doklady Akademii Nauk USSR, Moscow, Vol. 16, No. 2, 1962, pp. 263?266; english translation in Soviet Mathematics, Vol. 3, 1259?1263 (1962)
2. Baer, J.-L.: Weight-balanced trees. Proc. AFIPS, Vol. 44, 467?472 (1975)
3. Bayer, P.J.: Improved Bounds on the Costs of Optimal and Balanced Binary Search Trees. M. Sc. thesis, MIT, 1975
4. Bayer, R.: Symmetric binary B-trees: data structure and maintenance algorithms. Acta Informat. 1, 290?306 (1972)
5. Foster, C.C.: Information storage and retrieval using AVL-trees. Proceedings of the 20th National ACM Conference at Cleveland, 1965, pp. 192?205