In addition to the instruments discussed in this object group, the National Museum of American History's Division of Work and Industry owns a few parallel rules for nautical navigation made from scrimshaw and brass. Catalogues from manufacturers and distributors are part of the trade literature collections of the Smithsonian Institution Libraries.
Additionally, these museum databases include parallel rules among their collections, sometimes within cases of drawing instruments:
- Department of the History of Science, Harvard University, Waywiser, http://dssmhi1.fas.harvard.edu/emuseumdev/code/eMuseum.asp?lang=EN.
- Museum of the History of Science, Oxford, http://www.mhs.ox.ac.uk/collections/search/.
- National Maritime Museum, Greenwich, http://www.collections.rmg.co.uk/.
- National Museum of Australia, Canberra, http://www.nma.gov.au/collections-search/.
- Powerhouse Museum, Sydney, Australia, http://www.powerhousemuseum.com/collection/database/menu.php.
Parallel rules may also be found on historic ships and in historic homes, such as Thomas Jefferson's Monticello, http://www.monticello.org/site/research-and-collections/parallel-rule.
Hambly, Maya. Drawing Instruments, 1580–1980. London: Sotheby's Publications, 1988. Thorough and richly illustrated treatment of a full range of instruments.
Kidwell, Peggy A. "American Parallel Rules: Invention on the Fringes of Industry." Rittenhouse 10, no. 39 (1996): 90–96. Overview of the parallel rules in this object group.
Nautical Know How, Inc. "How to Use Parallel Rulers." BoatSafe.com, 2009. http://boatsafe.com/navigation/rules1.htm. Animated instructions for positioning parallel rules on navigational charts.
Riches, David M. "Parallel Rules: Rolling and Bar Types." http://www.mathsinstruments.me.uk/page39.html. Riches is a collector who has gathered photos and information on a variety of scientific and drawing instruments.
Stanley, William Ford. Mathematical Drawing and Measuring Instruments. 6th ed. London: E. & F. N. Spon, 1888. Treatise on the manufacture and operation of various instruments, including several forms of parallel rules.