Here  is a list of industry resources:

AAM – Alliance for Audited Media
Acculogix
American Association of Newspaper Distributors
Bosacks – Precision Media Group
Comag Marketing Group
CRS Media
Disticor Magazine Distribution Services
Distipress
Folio
Magazines Canada
MagNet
MBR – Magazines and Books at Retail
MPA
PMC – Periodical Marketers of Canada
Prologix
TNG
United Library Service