1. Analysis of the effectiveness of the NEC Directive on the tropospheric ozone levels in Portugal
2. BMNT (Federal Ministry of Sustainability and Tourism, Austria) (2019) National Air Pollution Control Programme.
3. BMU (German Federal Ministry for the Environment, Nature Conservation and Nuclear Safety) (2019) National Air Pollution Control Programme of the Federal Republic of Germany.
4. CARB (California Air Resources Board) (2017) Revised proposed 2016 state strategy for the state implementation plan.
5. CARB (California Air Resources Board) (2018) 2018 updates to the California state implementation plan.