"(...) analyzes folksonomy metadata for hierarchal semantic relationships via a content analysis of approximately 2000 folksonomy tags in over 600 individual entries. (...) The results indicate that hierarchical relationships are part of Folksonomies."
"TagOntology is about identifying and formalizing a conceptualization of the activity of tagging, and building technology that commits to the ontology at the semantic level."
N. Kuicheu, W. Ning, F. Narcisse, X. De, и F. Siewe. Information Science and Engineering (ICISE), 2009 1st International Conference on, стр. 2288 -2291. (декабря 2009)