When a system evolves, while the source code is changed documentation and traceability links are barely ever updated: maintaining traceability information between software artifacts is a costly and tedious activity frequently sacrificed during development and maintenance due to market pressure. This paper presents a new method to recovery traceability links between high level and low-level artifacts. The method is based on the partial knowledge of a subset of traceability links. It can be fully automated and the human intervention is only required to confirm or confute recovered traceability links. The method has been applied to software written in Java, to trace classes onto functional requirements, experimental result demonstrate the superiority of the novel method over the previously published results on the same system.