| Business | Phone |
| Am Market Research Frederick 21701 | (240) 446-2447 |
| Interviews Plus Inc 401 W Patrick St, Frederick 21701 | (301) 662-4782 |
| M & Rr Phone Room 1303 E Patrick St, Frederick 21701 | (301) 694-7861 |
| Marketing & Research Resources 1303a E Patrick St, Frederick 21701 | (301) 694-2800 |
| Trade Inflo 7311 Grove Rd # X, Frederick 21704 | (301) 831-4150 |