RT Web Page SR Electronic(1) ID 10335147 A1 P. J. Heggs T1 Fixed Beds YR 2015 FD 2015-04-24 NO Lessing rings, characteristic of, as packings for fixed beds, PB Begell House Inc. PP New York DO 10.1615/hedhme.a.000147 RD 2025-04-25 UL https://hedhme.com/content_map/?article_id=147&link_id=10335 WT HEDH Multimedia - Heat Exchanger Design Handbook, Multimedia Edition WP 2015-04-24