1. , , , , “Partitioning a tree into single-center subtrees to minimize flat service costs”, Technical Report, Universidad de Sevilla Dep. to de Estadistíca e Investigación Operativa, (in preparation).
2. A short note on graph tree partition problems with assignment or communication objective functions, Internal Report DEI 2001.7 ( 2001), Politecnico di Milano.
3. Combinatorial Optimization. Packing and Covering, SIAM, CBMS-NSF, Philadelphia, 2001.