The development of science with a rapid increase in the
number of scientific researches, scientists and researchers, and the advent of novel scientific disciplines have led
to an exponential rise in the number of journals, books,
congress proceedings, dissertations, patents, technical
reports and other publications bringing research results.
These publications are referred to as primary publications or primary sources of information, pointing to the original character of the information presented. Convenient
search of such a huge number of publications issued in
different countries, in different languages and stored in
different media would be impossible without special aids,
i.e. secondary publications or secondary information sources, which process, analyze and summarize primary publications and help in their target search. As such a great
amount of publications and their authors require proper
evaluation, these secondary sources of information are al-
so used for scientific validation, based on the high criteria
they employ in the selection of primary publications to
be systematically followed and processed.