Chanchala Kaddi R. Mitchell Parry May D. Wang Hypergeometric Similarity Measure for Spatial Analysis in Tissue Imaging Mass Spectrometry. 604-607 2011 BIBM http://doi.ieeecomputersociety.org/10.1109/BIBM.2011.113 conf/bibm/2011 db/conf/bibm/bibm2011.html#KaddiPW11