function random_imglink(){
  var myimages=new Array()
  //specify random images below. You can have as many as you wish
  myimages[1]="e-banner/Causal_Inference.gif"
  myimages[2]="e-banner/FDDD_Volume1.gif"
  myimages[3]="e-banner/FDDD_Volume2.gif"
  myimages[4]="e-banner/FDDD_Volume3.gif"
  myimages[5]="e-banner/FDDD_Volume4.gif"
  myimages[6]="e-banner/FDDD_Volume5.gif"
  //specify corresponding links below
  var imagelinks=new Array()
  	imagelinks[1]="http://www.benthamscience.com/ebooks/9781608051816/index.htm"
	imagelinks[2]="http://www.benthamscience.com/ebooks/9781608051991/index.htm"
	imagelinks[3]="http://www.benthamscience.com/ebooks/9781608052004/index.htm"
	imagelinks[4]="http://www.benthamscience.com/ebooks/9781608052011/index.htm"
	imagelinks[5]="http://www.benthamscience.com/ebooks/9781608052028/index.htm"
	imagelinks[6]="http://www.benthamscience.com/ebooks/9781608052035/index.htm"
  var ry=Math.floor(Math.random()*myimages.length)

  if (ry==0)
     ry=1
     document.write('<a href='+'"'+imagelinks[ry]+'"'+' onclick="window.open(this.href); return false;"><img src="'+myimages[ry]+'" border=0></a>')
}

  random_imglink()