1. Anthony L. (2012). AntConc3.1.3. http://www.antlab.sci.waseda.ac.jp/antconc_index.html (accessed 29 April 2014).
2. The Bradford's law: A new calculus for the social sciences?;Brookes;Journal of the American Society for Information Science,1979
3. Davies M. (2008–2014). The Corpus of Contemporary American English: 450 million words, 1990-present. http://corpus.byu.edu/coca/ (accessed 16 April 2015).
4. Davies M. (2010–2014). The Corpus of Historical American English: 400 million words, 1810–2009. http://corpus.byu.edu/coha/ (accessed 16 April 2015).
5. Bradford's law; theory, empiricism and the gaps between;Drott;Library trends,1981