http://www.sciencedirect.com/science/article/pii/S0093691X04001074
https://www.jstage.jst.go.jp/article/jvms/63/3/63_3_293/_article
http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0048104
http://europepmc.org/abstract/cba/523020
http://www.jstor.org/stable/3872955?seq=1#page_scan_tab_contents
http://onlinelibrary.wiley.com/doi/10.1046/j.1365-294X.1997.00281.x/abstract
http://www.jstor.org/stable/3873007?seq=1#page_scan_tab_contents
http://www.ncbi.nlm.nih.gov/pubmed/17201199
http://www.ncbi.nlm.nih.gov/pubmed/7697192