The alias is mostly just J. Riegen (not Julius Riegen).
Under the joined alias Bohrmann-Riegen, J. Riegen produced several libretti in collaboration with Heinrich Bohrmann. [1][2][3][4]
Birth & death dates (1843-1895) are from death registration (Vienna, Mariabrunn parish, 1895, RegN°37) [5] for Julius Nigri, Schriftsteller (=writer), geb. in Mailand (b. Milano), very likely to be the librettist J. Riegen, known to reside in Weidlingau (part of that Mariabrunn parish) in 1893. [6][7] Many other sources give 1849 (year only) as birth date.
