Solms-Braunfels Archives, 1842-1957. Dolph Briscoe Center for American History, The University of Texas at Austin. Finding aid.

Sousa Press Books. U.S. Marine Band Library, Washington, D.C.

Spreckels Sugar Company Collection. University of California at Davis Special Collections. Finding Aid.

Steinway & Sons Collection. LaGuardia and Wagner Archives, Queens, New York. Online access.

Stiegel, Henry William, 1729-1785, Records of Manheim Glass Works 1763-[1773?]. Winterthur Museum, Garden, and Library, Wilmington, DE.

Straus Family Papers, 1810-1962. Manuscripts and Archives Division, New York Public Library. Finding Aid.

"The Man Who Makes the Stamps Stick." Baltimore Sun Magazine April 21, 1929, 12.

The Story of Brach. Chicago: E. J. Brach and Sons, 1923.

Timken Company Archives. Canton, OH.

Walter P. Paepcke Papers. Special Collections Research Center, University of Chicago Library. Finding aid.

Werner Frank Oral History. conducted by Jeffrey Yost, Mountain View, CA, February 14, 2006, Computer History Museum. Transcript online.

Western Sugar Refinery Records, 1871-1949. Bancroft Library, University of California, Berkeley. Finding Aid.

Weyerhaeuser family. Weyerhaeuser family papers. Weyerhaeuser Reading Room, Minnesota Historical Society, St. Paul, Minnesota. Finding aid.

William Blum Thalhimer, Jr. Corporate and Family Archives, 1862-1992. Mss1 T3275a FA1, Virginia Historical Society, Richmond, VA. Finding aid.

"William Klein." Cyclopedia of American Biography. New York: James T. White, 1892–1984.

Wistar Family Papers. Historical Society of Pennsylvania, Philadelphia [HSP].

Wurlitzer Company Records, 1860-1984. The Archives Center of the National Museum of American History. Finding Aid.

Yerkes Observatory. Office of the Director. Records, Special Collections Research Center, University of Chicago Library. Finding aid.

Breschini, Gary S., Mona Dudgel, and Trudy Haversat. Images of America: Spreckels. Charleston: Arcadia Publishing, 2006.

Adam, Thomas. Buying Respectability: Philanthropy and Urban Society in Transnational Perspective, 1840s to 1930s. Bloomington: Indiana University Press, 2009.