As Susanna (or, in German, perhaps "Susanne") was born in Germany: The family name "Woulf" obviously doesn't exist there at all. The original FN could have either been Wolf/Wolff, or Wulf/Wulff, respectively - with enormous entry numbers in the German phone book nowadays > 10,000. On the other hand, the family name "Wolmer" does indeed exist in Germany, but only extremely rarely with nowadays 14 entries in total. Contariwise, and I am very much used to this as a model train enthusiast, the family name "Vollmer" has almost 7.000 phone book entries. Look perhaps, among others, to Vollmer Co., manufacturer of model train buildings.