Brain Transcriptome Database (BrainTx)http://rdf.ncbi.nlm.nih.gov/pubmed/

Matthew J. Kohn, et.al., The acrosomal protein Dickkopf-like 1 (DKKL1) facilitates sperm penetration of the zona pellucida., Fertility and sterility, 2010, 93
http://rdf.ncbi.nlm.nih.gov/pubmed/19596312