First observation of the fourth neutral polarization point in the atmosphere Horváth, Gábor ; Bernáth, Balázs ; Suhai, Bence ; Barta, András ; Wehner, Rüdiger Abstract Publication: Journal of the Optical Society of America A Pub Date: October 2002 DOI: 10.1364/JOSAA.19.002085 Bibcode: 2002JOSAA..19.2085H