Małgorzata Kozak, Simple procedural infraction or a serious obstruction of antitrust proceedings - are fines in the region of 30-million EURO justified? Case comment to the decisions of the President of the Office for Competition and Consumer Protection of 4 November 2010 Polska Telefonia Cyfrowa Sp. z o.o. (DOK-9/2010) and of 24 February 2011 "Polkomtel SA" (DOK-1/2011) , Yearbook of Antitrust and Regulatory Studies, 2011, 4 (5), , s. 283-290