Balanced ternary tree

I was wondering if anyone has implemented a Balanced Ternary Tree module for haskell. According to http://www.ddj.com/documents/s=921/ddj9804a/9804a.htm this would be a better datastructure for symbol tables than the binary tree I am currently using: * Each string is a key, which makes for O(n/2 * log m) comparisons where n is the average string length and m is the number of string in the table, * A balanced ternary tree would be O(n + log m). (DDJ's code does not balance the tree) Sengan