Czech ceramic artist Helena Johnova worked in the period 1909-1918 in Vienna, where she studied by prof. Michael Powolny and she owned with R. Neuwirth and I. Schwetz-Lehmann the firm Keramische Werkgenossenschaft there. (en)
Česká keramička Helena Johnová působila v letech 1909-1918 ve Vídni, kde studovala u prof. Michaela Powolneho a spolu s R. Neuwirthovou a I. Schwetz -Lehmann vlastnila firmu Keramische Werkgenossenschaft