Polymeric sheets having on one or both sides a fabric texture and, optionally, a network of elongated channels in the interior of the structural framework of the sheets. The sheets comprise a plurality of interbonded continuous polymeric ribs extending in a direction parallel to the plane of the sheets....http://www.google.fr/patents/US4175557?utm_source=gb-gplus-shareBrevet US4175557 - Polymeric sheets
