var imageFiles_bk_13 = new Array();
imageFiles_bk_13['0'] = new Array ('_images/bk_More_References.gif', '_images/bk_More_ReferencesMouseover.gif');

function image_on_bk_13 (position) {
   var doc = eval("document.imagebk_13" + position);
   doc.src = imageFiles_bk_13[position][1];
}

function image_off_bk_13 (position) {
   var doc = eval("document.imagebk_13" + position);
   doc.src = imageFiles_bk_13[position][0];
}