Swiger Coil Systems. "Edgewound Coils". Swiger Coil Systems, A Wabtec Company. Archived from the original on 19 December 2010. Retrieved 1 January 2011.
Swiger Coil Systems. "Edgewound Coils". Swiger Coil Systems, A Wabtec Company. Archived from the original on 19 December 2010. Retrieved 1 January 2011.
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One or more of the preceding sentences incorporates text from a publication now in the public domain: Chisholm, Hugh, ed. (1911). "Wire". Encyclopædia Britannica. Vol. 28 (11th ed.). Cambridge University Press. pp. 738–739.