Wassmann, Dietrich (transl. and ed.). Collection of Oromo hymns. Duplicated in Aira in the 1930s.
The hymnal contains 26 songs:
Source: ELM Hermannsburg Archives
It appears that the translation of hymns continued (under the supervision of Friedrich Bock) until the missionaries had to leave the country in 1936.
Cross references
Overview of Oromo hymns translated / edited by Rev Dietrich Wassmann