Biographical Database of NAWSA Suffragists, 1890-1920
Biography of Dr. Nellie V. Mark, 1857-1935
Wikipedia sketch accessible at: https://en.wikipedia.org/wiki/Nellie_V._Mark
See also Leonard, John William (1914). Woman's Who's who of America: A Biographical Dictionary of Contemporary Women of the United States and Canada [LINK]
Dr Mark marched in the March 1913 suffrage parade in Washington, D.C. and submitted a notarized statement on behalf of the of the abuse hurled at marchers by state militia and the failure of DC police to intervene to protect the marchers. See United States Congress, Suffrage Parade: Hearings Before a Subcommittee of the Committee on the District of Columbia, United States Senate, Sixty-Third Congress (Washington: Government Printing Office, 1913), p. 461.