21. [Sigard Adolphus Knopf] Publication: , 1900 Subject(s): Knopf, S. Adolphus (Sigard Adolphus), 1857-1940.
22. [Sigard Adolphus Knopf] Publication: Bellport. , 1901 Subject(s): Knopf, S. Adolphus (Sigard Adolphus), 1857-1940.
23. [Sigard Adolphus Knopf] Publication: 1902 Subject(s): Knopf, S. Adolphus (Sigard Adolphus), 1857-1940.