1. The complexity of the traveling repairman problem;Afrati;Informatique Theorique et Applications (Theoretical Informatics and Applications),1986
2. Approximation schemes for minimum latency problems;Arora,1999
3. The minimum latency problem;Blum,1994
4. An improved approximation ratio for the minimum latency problem;Goemans,1996
5. A 3-approximation for the minimum tree spanning k vertices;Grag,1996