| 1 | What is biogas | [1] s. 49-56 |
| 2 | Nutrients that can be used in biogas production | [1] s. 57-77 |
| 3 | Biochemical reactions in biogas production | [1] s. 93-127 |
| 4 | Pretreatments in biogas process | [1] s. 223-231 |
| 5 | Pretreatments in biogas process | [1] s. 235-243 |
| 6 | Biogas process to be taken into account when matters | [2] s. 171–185 |
| 7 | Biogas process to be taken into account when matters | [2] s. 186-200 |
| 8 | Optimization of operating parameters in biogas production | [3] s. 738-748 |
| 9 | Biogas enrichment | [1] s. 333-344 |
| 10 | Biogas enrichment | [1] s. 345-355 |
| 11 | Effect of metal-based conductive material on biogas production increase | [4] s. 10241–10253 [5] s. 698-707 |
| 12 | Effect of metal-based conductive material on biogas production increase | [4] s. 10241–10253 [5] s. 698-707 |
| 13 | Biogas use for electricity and heat generation | [1] s. 361-388 |
| 14 | Biogas plant construction stages (Feasibility, preparation, construction process) | [1] s. 189-192 |