1. Kulušić, I. (2019). Status Prirodnog Plina Kao Tranzicijskog Goriva u Europskoj Uniji i Republici Hrvatskoj. [Master’s Thesis, University of Zagreb].
2. Analysis of renewable energies in European Union;Pacesila;Renew. Sustain. Energy Rev.,2016
3. Alternative Fuels in Transport as Energy Security Factor in European Union;Transp. Econ. Logist.,2017
4. Cătuţi, M., Egenhofer, C., and Elkerbout, M. (2019). The Future of Gas in Europe: Review of Recent Studies on the Future of Gas, Available online: https://aei.pitt.edu/100397/1/RR2019-03_Future-of-gas-in-Europe.pdf.
5. Natural gas as a marine fuel;Thomson;Energy Policy,2015