1. Bentley, J. L. and A. C. Yao, An almost optimal algorithm for unbounded searching, Inf. Proc. Letters 5 (1976) 82–87.
2. Blum, M., R. W. Floyd, V. R. Pratt, R. L. Rivest, and R. E. Tarjan, Time bounds for selection, J. Comput. Sys. Sci. 7 (1972) 448–461.
3. Chandrasekaran, R. and A. Daughtey, Problems of location on trees, Disc. Paper 357, Ctr. for Math. Studies in Econ. and Mgmt. Sci., Northwestern U., 1978.
4. Chandreskaran, R. and A. Tamir, Polynomially bounded algorithms for locating P-centers on a tree, Disc. Paper 358, Ctr. for Math. Studies in Econ. and Mgmt. Sci., Northwestern U., 1978.
5. Chandrasekaran, R. and A. Tamir, An 0((nlogP)2) algorithm for the continuous P-center problem on a tree, Disc. Paper 367, Ctr. for Math. Studies in Econ. and Mgmt. Sci., Northwestern U., 1978.