Roy Lewallen wrote"
"Do you have a reference which defines field strength in terms of
voltage induced in a wire?"

Here is more of one I already posted. It is from the 19th edition of the
ARRL Antenna Book on page 23-3:
"The strength of a wave is measured as the voltage between two points
lying on an electric line of force in the plane of the wave front. The
standard of measure for field intensity is the voltage developed in a
wire that is 1 meter long, expressed as volts per meter. (If the wire
were 2 meters long, the voltage developed would be divided by two to
determine the field strength in volts per meter.)"

Best regards, Richard Harrison, KB5WZI