Sears, M. W.; Zemansky (1964). „Equilibrium of a Particle”. University Physics (3rd izd.). Addison-Wesley. str. 26–27. LCCN63015265. »A body whose rotation is ignored as irrelevant is called a particle. A particle may be so small that it is an approximation to a point, or it may be of any size, provided that the action lines of all the forces acting on it intersect in one point.«
Jefimenko, Oleg D. (1994). „Direct calculation of the electric and magnetic fields of an electric point charge moving with constant velocity”. American Journal of Physics62 (1): 79–85. DOI:10.1119/1.17716.
Sears, M. W.; Zemansky (1964). „Equilibrium of a Particle”. University Physics (3rd izd.). Addison-Wesley. str. 26–27. LCCN63015265. »A body whose rotation is ignored as irrelevant is called a particle. A particle may be so small that it is an approximation to a point, or it may be of any size, provided that the action lines of all the forces acting on it intersect in one point.«
