The purpose of traceability is to ensure persistent alignment of product knowledge between stakeholders, artifacts, and traceability objects. On the other hand, process knowledge is equally important to ensure a systematic software development process with accurate specification and verifiable quality attributes. Previous studies lacks in presenting a consolidated view from product and process knowledge perspectives. This study has taken a systematic literature review approach to evaluate sixty one previously published papers on traceability in leading journals and conferences. Based on the findings, the authors propose to extend the definition of an existing traceability meta-model to combine both product and process knowledge perspectives. The scope of this paper is to define the extension of the traceability meta-model without violating any of its statements. This study aims to contribute by taking steps towards defining a holistic model of traceability that will provide practical guidelines to IT practitioners in general and to process engineers in particular.