acf	Autocovariance function Estimation
ar	Fit autoregressive models to time series
ar.yw	Fit autoregressive model by solving Yule-Walker equations
plot.acf	Autocovariance function Estimation
plot.spec	Spectral Density Estimation
spec	Spectral Density Estimation
spec.pgram	Estimate spectral density of a time series from smoothed periodogram
spectrum	Spectral Density Estimation
