http://r-forge.r-project.org/tracker/download.php/103/458/5316/2651/low-sperm-count-is-it-curable-low-sperm-count-is-it-hereditary-low-sperm-count-iui-bfp-low-sperm-count-iui-or-ivf-low-sperm-count-iui-success-rate.html