| Title | Age |
|---|---|
| pressure regulation | 8 years, 17 weeks and 5 days |
| volume measuring | 8 years, 17 weeks and 5 days |
| leakage detection and control | 8 years, 17 weeks and 5 days |
| construction and maintenence | 8 years, 17 weeks and 5 days |
| table engineering | 8 years, 17 weeks and 5 days |
| all-ions day | 8 years, 17 weeks and 5 days |
| GAS FLOW CALCULATIONS | 8 years, 17 weeks and 5 days |
| tempering load | 8 years, 17 weeks and 5 days |
| basic of science | 8 years, 17 weeks and 5 days |
| gas industry plan | 8 years, 17 weeks and 5 days |