Heuer-Christen studied singing in Bern with Maria Helbling , in Freiburg with Margarethe von Winterfeldt and in Zurich with Dorothea Ammann-Goesch .
ADJ VERB NOUN ADP PROPN ADP PROPN PROPN , ADP PROPN ADP PROPN PROPN PROPN CCONJ ADP PROPN ADP PROPN PROPN .