Literature reviews aim to map and evaluate the body of literature and identify potential research gaps highlighting the
boundaries of knowledge (Tranfield et al., 2003). Structured literature reviews are completed through an iterative cycle of
defining appropriate search keywords, searching the literature and completing the analysis (Saunders et al., 2009).
Rowley and Slack (2004) recommend a structured methodology for scanning resources, designing the mind map to structure
the literature review, writing the study and building the bibliography. Seuring and Gold (2012) present content analysis as
an effective tool for conducting a systematic and transparent literature review through four steps of material collection,
descriptive analysis, category selection and material evaluation. Inspired by the work of Rowley and Slack (2004) and
Seuring and Gold (2012), we use a four-step methodology for data collection and comprehensive evaluation of the field aiming
to identify the most influential studies, determine the topical areas of current research interest and provide insights for
current research interests and directions for future research in the field.