Here is a [random, scattered, incomplete] list of extensions to Lucas's theory that I am interested in : 
	- relativistic correction factor is not correct, get rid of (1 - beta^2) terms (Ed Dowdye Jr?)
	- time lags and causality,  Oleg Jefimenko
	- fractional order calculus - ?Johan Suyken's student, now prof?
	- 

Comparisons to : 
	- Randall Mills