The O'Brien Trophy, or O'Brien Cup, as labelled on the trophy itself, is a retired trophy that was awarded in the National Hockey Association (NHA) and the National Hockey League (NHL) ice hockey leagues of North America from 1910 to 1950.
* How Stuff Works - Gas Masks* Gas Masks Guide to selecting safe and dependable gas masks* Your Gas mask Guide to the maintenance of your gas mask* Respirator Fact Sheet* CBRN SCBA NIOSH Approved Respirators List of NIOSH Approved CBRN SCBA respirators* World War 1 gas mask technology - "Combating Man's Deadliest Peril: How the unending struggle between gas and mask is carried on", Popular Science monthly, December 1918, page 64, Scanned by Google Books: http://books.google.com/books?id=EikDAAAAMBAJ&pg=PA64