1.1. Data extraction and data analysis
From each paper common elements of bibliographic data were extracted using a Java
text parser implemented by one of the authors, namely: authors, institution and
nationality of authors, the year of the publication, the name of the paper source,
number of citations, the total number of reference, type of the document and the age of
a references. The extracted bibliographic data were recorded in Excel document;
preprocessed using built in Excel functions and then transferred into SPSS for further
analysis. Within the data analysis we performed descriptive methods and correlations