We discovered that the perturbation was coming from a fight in the neighbor's yard.

Frank Herbert Brownell has written:

'Explicit perturbation formulae and convergence theorems' -- subject(s): Convergence, Perturbation theory (Mathematics), Perturbation (Mathematics)

Ji-Huan He has written:

'Perturbation methods' -- subject(s): Perturbation (Mathematics)

Perturbation

Stephen M. Omohundro has written:

'Geometric perturbation theory in physics' -- subject(s): Differential Geometry, Perturbation (Mathematics), Perturbation (Quantum dynamics), Plasma (Ionized gases), Statistical mechanics