| commonwealthlawyers.com | Commonwealth Lawyers Association (CLA) |
| cto.int | Commonwealth Telecommunications Organization |
| cata-tax.org | Commonwealth Association of Tax Administrators |
| casle.org | Commonwealth Association of Surveying and Land Economy (CASLE) |
| cbcglobelink.org | Commonwealth Business Council |
| cpu.org.uk | Commonwealth Press Union |
| cpahq.org | Commonwealth Parliamentary Association |
| commonwealthtuc.org | Commonwealth Trade Union Council |
| commonwealth.org.uk | Commonwealth Institute |
| commat.org | Commonwealth Medical Association Trust (COMMAT) |
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