| Business | Phone |
| Core Technology Group Inc 7249 Pryor Rd, Billings 59101 | (406) 248-1864 |
| Specialized Accounting Svc 1302 24th St W # 216, Billings 59102 | (406) 861-4463 |
| Prometric 1004 Division St, Billings 59101 | (406) 294-8613 |
| Entre Information Systems 2727 Central Ave, Billings 59102 | (406) 256-0300 |
| North American Indian Sys Po Box 50815, Billings 59105 | (406) 671-4883 |