ELECTRONIC	h   t   t   p   c o l o n   s l a s h   s l a s h   a d s a b s dot h a r v a r d dot e   d   u   s l a s h   a b s   s l a s h   n i n e t e e n   n i n e t y   c e m d a	http://adsabs.harvard.edu/abs/1990cemda	1