This short paper deals with the delineation of research issues based on bibliographic coupling of publications assisted by visualization techniques. Cluster techniques, multidimensional scaling or spring models reveal agglomerations of similar publications but it is always difficult to have a clear picture of the thematic substructure of a research field or even a set of publications with a consistent content. The central research questions of this work are: How can we visualize the occurrence of cited references in an agglomeration of similar publications? Does the visualization of the occurrence of cited reference in bibliographically coupled publications help to understand how to delineate a research topic? Research fronts were defined as a local agglomeration of similar publications in a two dimensional space. This work proposes a visualization method using an overlay technique in 2D heat maps of bibliographically coupled publications. With this approach we could visualize and discuss to what extend research fronts are formed by several highly cited references that are the core of the underlying knowledge base. The approach is demonstrated for research related to foresight.
Keywords: Bibliographic coupling, Science mapping, Visualization, Overlay technique, Delineation of research issues.