ZVIRGZDIŅŠ, Indulis. Professional and Social Activities of Engineer Jānis Jagars (1894–1970). History of Engineering Sciences and Institutions of Higher Education, Riga, Latvia, v. 5, p. 107–129, 2021. DOI: 10.7250/HESIHE.2021.006. Disponível em: https://hesihe-journals.rtu.lv/hesihe/article/view/HESIHE.2021.006.. Acesso em: 6 mar. 2026.