function toggleAbstract(){
	var abstracts = document.getElementsByTagName('div');
	
	for (var i=0; i<abstracts.length; i++){
		 if (abstracts[i].className == 'abstract'){
			if (abstracts[i].style.display == 'block'){
				abstracts[i].style.display = 'none';
			}
			else {
				abstracts[i].style.display = 'block';
			}
		}
	}
}