Ivkov, Vesna. 2013. “Tracing the Oldest Audio Recordings of Vocal Musical Tradition of Germans in Bačka: The Field Research of Gustav Kipers-Sonenberg in Bačka”. Etnoantropološki Problemi Issues in Ethnology and Anthropology 8 (2):585-96. https://doi.org/10.21301/EAP.v8i2.12.