Zigmunde, Alīda, and Elita Stikute. “Versatile Pedagogical and Social Activities of a Graduate of Riga Polytechnic Institute Jānis Stiprais (1870–1946)”. History of Engineering Sciences and Institutions of Higher Education, vol. 5, Oct. 2021, pp. 93-106, https://doi.org/10.7250/HESIHE.2021.005.