| Business | Phone |
| Beckford Investigation Po Box 851, Brentwood 94513 | (925) 516-9111 |
| Mark Flynn & Assoc Po Box 1418, Brentwood 94513 | (925) 516-1522 |
| Fridley & Assocs Brentwood 94513 | (925) 634-3034 |
| Mercantile Systems & Surveys Brentwood 94513 | (925) 240-8000 |