Release of volatile organic compounds (VOCs) from the lung cancer cell line CALU-1 in vitro Wojciech Filipiak, Andreas Sponring, Tomáš Mikoviny, Clemens Ager, Jochen K. Schubert, Wolfram Miekisch, Anton Amann and Jakob Troppmair 2008 doi:10.1186/1475-2867-8-17 pdf