Biogas has been used as vehicle fuel since the 1930s. Pioneering countries were Germany in the 1930s and Sweden and Finland in the 1940s. Study on the history of biogas in transportation applications was published in journal Finnish Quarterly for the History of Technology:
Lampinen Ari (2013) Development of biogas technology systems for transport . Finnish Quarterly for the History of Technology (Tekniikan Waiheita) 31(3)5-37.