Pulsating or not? A search for hidden pulsations below the red edge of the ZZ Ceti instability stripR. Kotak, M. H. van Kerkwijk, J. C. Clemens and T. A. BidaA&A, 391 3 (2002) 1005-1012DOI: https://doi.org/10.1051/0004-6361:20020846