| ari.org | ARI CoolNet |
| acca.org | Air Conditioning Contractors of America |
| nspe.org | National Society of Professional Engineers |
| cal-smacna.org | California Association of Sheet Metal and Air Conditioning Contractors (CAL-SMAC |
| amcaqld.com.au | Air Conditioning & Mechanical Contractors Association of Queensland (AMCA-Q) |
| ul.com | Underwriters Laboratories Inc. |
| smwia.org | Sheet Metal Workers' International Association |
| rses.org | Refrigeration Service Engineers Society |
| phccweb.org | Plumbing-heating-cooling Contractors–national Association Web Site |
| nrca.net | NRCA, The National Roofing Contractors Association |
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