Columbia subject headings:
Asymptotic expansions.
Differential equations, Nonlinear--Asymptotic theory.
Oscillations.
Harvard subject headings:
Asymptotic expansions.
Differential equations, Nonlinear--Asymptotic theory.
Oscillations.
Princeton subject headings:
Asymptotic expansions.
Differential equations, Nonlinear--Asymptotic theory.
Oscillations.