• History of the terms electromagnetism and electrodynamics
• P.M Harman. Energy, Force, and Matter: The Conceptual Development of Nineteenth-Century Physics.
• "Scientific Realism". Stanford Ency. of Philosophy. "See 4.1 Empiricism" for a discussion of instrumentalism
• Review of Heilbron, Electricity in the 17th and 18th Centuries: A Study of Early Modern Physics.
• Rene Taton (ed.), Science in the Nineteenth Century. See Part III. Physical Science, Chapter 4. Bauer. "Electricity and Magnetism".
• Mathias Frisch. Philosophical Issues in Electromagnetism.
• Mathias Frisch. Conceptual problems in classical electrodynamics: No more toils and trouble?

Frank Close. Nothing: A Very Short Introduction.  See Chapter 4, "Waves in What?". See also the Index on the concept of the ether. Re. the status of the ether in relativistic theory, see here:

"With this confirmation of Einstein's theory, we are led to a picture of space-time as acting like an elastic medium, which is reminiscent of the very ether that Einstein's work on electromagnetic radiation, his special theory of relativity, had done so much to eradicate. However, relativity does not imply that there is no ether, only that any stuff in that ether must behave in accord with the principles of relativity! An example of ‘ether’ is an electric field, which you cannot see unless you make it oscillate: then you literally can. A relativistic ether requires both electric and magnetic fields, changes in which travel at light speed. Analogously for the ether of a gravitational field, gravitational waves – ripples in the metric of space-time – also travel at the universal speed of light."

Other resources:

• Close, Frank. Void. 
• Decaen, Christopher. The Impossibility of Action at a Distance.      Also,  Aristotle’s Aether and Contemporary Science. 
• Eisenhart, Churchill . The Ether: Riddle of the Ages. 
• Hesse, Mary. Forces and fields; the concept of action at a distance in the history of physics.
• Kragh, Helge. Empty space or ethereal plenum? Early ideas from Aristotle to Einstein
• Paiva de Andrade, Elaine Maria; Faber, Jean; Pinguelli Rosa, Luiz.  A Spontaneous Physics Philosophy on the Concept of Ether Throughout the History of Science: Birth, Death and Revival. Contains some bibliographic references to contemporary invocations of the ether concept.
• Whittaker, E. T. A history of the theories of aether and electricity : from the age of Descartes to the close of the nineteenth century