| iiar.org | International Institute of Ammonia Refrigeration |
| hardinet.org | Heating, Airconditioning and Refrigeration Distributors International |
| gamanet.org | Gas Appliance Manufacturers Association |
| smacna.org | Sheet Metal and Air Conditioning Contractors' National Association (SMACNA) |
| phccweb.org | Plumbing-heating-cooling Contractors–national Association Web Site |
| nspe.org | National Society of Professional Engineers |
| natex.org | North American Technician Excellence (NATE) |
| naphcc.org | Phcc National Association |
| mcaa.org | The Mechanical Contractors Association Of America! |
| hrai.ca | Hrai - The Heating, Refrigeration And Air Conditioning Institute Of Canada |
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