S. FRIES, A Chronological Bibliography of Latgalian Printed Texts from the 18th to Early 20th Centuries. Rēzekne, Latvia: RTU Rēzeknes akadēmija, 2023. Accessed: Apr. 02, 2025. [Online]. Available: https://books.rta.lv/index.php/RTA/catalog/book/28