| Business | Phone |
| Millot Engineering Group 209 S Citrus Ave # 5, Covina 91723 | (626) 966-4251 |
| Stetson Engineers Inc 861 S Village Oaks Dr # 100, Covina 91724 | (626) 967-6202 |
| Bergey Arthur L 1380 N Citrus Ave, Covina 91722 | (626) 331-1666 |
| Gvw Engineering Inc 869 E Cypress St, Covina 91722 | (626) 938-0411 |