E.  Drymonas, Zervanou, K., and Petrakis, E. G. M., ?Exploiting multi-word similarity for retrieval in medical document collections: The TSRM approach?, Journal of Digital Information Management, vol. 8, no. 5, pp. 315 - 321, 2010.

N.  Hourdakis, Argyriou, M., Petrakis, E. G. M., and Milios, E. E., ?Hierarchical clustering in medical document collections: The BIC-means method?, Journal of Digital Information Management, vol. 8, no. 2, pp. 71 - 77, 2010.

E. G. M.  Petrakis, Varelas, G., Hliaoutakis, A., and Raftopoulou, P., ?X-Similarity: Computing Semantic Similarity between concepts from different ontologies?, Journal of Digital Information Management, vol. 4, no. 4, pp. 233 - 237, 2006.