Publisher
- Clarkson Research Studies Clarkson Research Services Limited275
- Mercator Media Limited46
- Department for Transport9
- Routledge6
- Springer5
- IHS Markit3
- [Belfast Harbour Commissioners]3
- Adlard Coles Nautical2
- CRC Press2
- KoganPage2
- Londonderry Port and Harbour Commissioners2
- Palgrave Macmillan2
- Warrenpoint Harbour Authority2
- Amberley Publishing1
- CRC Press/Balkema1
- Cambridge Scholars Publishing1
- Coleraine Harbour Commissioners1
- Elsevier1
- Glen Segell1
- HISTORY PRESS1