| GRB-54-03 | German Position on new limit values for 03 series of amendments to R51 | |
| GRB-55-01 | Japanese Position on new limit values for 03 series of amendments to Regulation No. 51 | |
| GRB-56-01 | Japan position on new limit values for 03 series of amendments to Regulation No. 51 | |
| GRB-56-05 | Japanese proposal on R51 limit values | |
| GRB-56-07 | Proposal for new sound limit values in the draft 03 series of amendments to UN R51 | |
| GRB-57-05 | UN R51: China is finding common solutions for M1 and N1 sub-categories | |
| GRB-57-06 | UN R51: Chinese suggestions on subcategories of commercial vehicles | |
| GRB-57-07 | UN R51: Sub-categories table suggestion from China | |
| GRB-57-19 | OICA position on Vehicle Classification, Limits and Dates in UN Regulation No. 51.03 | |
| GRB-57-22 | Japanese proposal on R51 limit values: Rationale for N2 and M3 thresholds | |
| GRB-57-23 | Vehicle Noise: Analysis of Swiss database and EC, Germany, and Japan noise proposals | |
| GRB-57-28 | Reducing Vehicle Noise Emissions: Update on the new EU Commission legislative proposal | |
| GRB-57-28 | Reducing Vehicle Noise Emissions: Update on the new EU Commission legislative proposal | |
| GRB/2012/7 | Proposal for the 03 series of amendments to Regulation No. 51 | |
| GRB/2013/4 | Proposal for Supplement 9 to the 02 series of amendments to Regulation No. 51 |