Table II.

Relevant terms in q_k and u_k for k ≤ 4

k	Relevant terms in qk	Relevant term in uk
1	x	$\frac{1}{{\mu }_0}\dot{x}$
2	$x^2,\frac{1}{{\mu }_0}x\dot{x}$	$\frac{1}{{\mu }_0{\mu }_1}x\ddot{x}$
3	$x^4,\frac{2}{{\mu }_0}{x}^3\dot{x},\frac{1}{{\mu }_0{\mu }_1}{x}^3\ddot{x}$	$\frac{1}{{\mu }_0{\mu }_1{\mu }_2}{x}^3{x}^{\left(3\right)}$
4	$$x^8,\frac{4}{{\mu }_0}{x}^7\dot{x},\frac{2}{{\mu }_0{\mu }_1}{x}^7\ddot{x},\frac{1}{{\mu }_0{\mu }_1{\mu }_2}{x}^7{x}^{\left(3\right)}$$	$\frac{1}{{\mu }_0{\mu }_1{\mu }_2{\mu }_3}{x}^7{x}^{\left(4\right)}$