Spectral estimation with differencing/nonlinear trend estimator: McGonigle, E. T., Killick, R., and Nunes, M. (2022). Modelling
time-varying first and second-order structure of time series via wavelets
and differencing. Electronic Journal of Statistics, 6(2), 4398-4448.
Spectral estimation in presence of trend/linear trend estimator: McGonigle, E. T., Killick, R., and Nunes, M. (2022). Trend
locally stationary wavelet processes. Journal of Time Series
Analysis, 43(6), 895-917.
LSW processes without trend: Nason, G. P., von Sachs, R., and Kroisandt, G. (2000). Wavelet processes and
adaptive estimation of the evolutionary wavelet spectrum. Journal of
the Royal Statistical Society: Series B (Statistical Methodology), 62(2), 271--292.
lacf estimation without trend: Nason, G. P. (2013). A test for second-order stationarity and approximate
confidence intervals for localized autocovariances for locally stationary
time series. Journal of the Royal Statistical Society: Series B
(Statistical Methodology), 75(5), 879--904.