The number of research papers published in scientific journals is exponentially increased during the last years. In a recent study by Van Noorden, based on publications in Web of Science, it is demonstrated that the growth rate of publications, was 1% in the 18th century, to 2 to 3% in the period between the two world wars, and 8 to 9% up to 2010. This evolution of scientific output is equivalent to a doubling every nine years. Thus, when writing a review paper, a research project proposal or a significant part of any research paper regarding the related literature, a researcher is called to analyze a vast amount of research papers.

Accordingly, new terminology, as well as techniques, appear, like bibliometric analysis, bibliometrics, scientometrics, scientific mapping etc., where with the aid of computer algorithms, it is possible to analyze a vast amount of research papers, strengthening the elementary reviews made by individual researchers. The main purpose of this numerical elaboration is to construct bibliometric maps of the studied field. Bibliometric maps reveal associations of keywords, authors, journals as well as references, though their distances on a two-dimensional map, exhibiting significant information about how the studied papers are interrelated, by their simultaneous appearance in research works. Thus, the conclusions regarding the scientific field studied, are based on an extended database of papers, and through a rigor computational procedure, the outcome is precisely documented.