| Business | Phone |
| D A Morton Surveying 12 David St, Markham L3P 1Z9 | (905) 294-2994 |
| J D Barnes Ltd 145 Renfrew Dr, Markham L3R 9R6 | (905) 477-3600 |
| R G Mc Kibbon Ltd 176 Bullock Dr #10, Markham L3P 7N1 | (905) 294-3754 |
| Yates & Purcell Ltd 16 Esna Park Dr #107, Markham L3R 5X1 | (905) 479-6500 |
| David Horwood Ltd 3980 14th Ave, Markham L3R 0B1 | (905) 475-7265 |
| E W Bowyer Inc 9275 Highway 48, Markham L6E 1A3 | (905) 294-8093 |