See also: Emission Regulations: Retrofit Programs
- Diesel Retrofit in Europe
AECCInformation on diesel retrofit programs in the European Union, including technology, news, and funding.
- Retrofit Tool Kit
Diesel Technology ForumInformation on diesel retrofit programs and their funding in the United States.
- Diesel Retrofit Technology
MECAInformation on diesel retrofit emission control technologies, including manufacturers, projects, news, funding, and technical papers.