| qdft | Quantile Discrete Fourier Transform (QDFT) |
| qdft2qacf | Quantile Autocovariance Function (QACF) |
| qdft2qper | Quantile Periodogram and Cross-Periodogram (QPER) |
| qdft2qser | Quantile Series (QSER) |
| qfa.plot | Quantile-Frequency Plot |
| qkl.divergence | Kullback-Leibler Divergence of Quantile Spectral Estimate |
| qper2qcoh | Quantile Coherence Spectrum (QCOH) |
| qsmooth.qdft | Quantile Smoothing of Quantile Discrete Fourier Transform |
| qsmooth.qper | Quantile Smoothing of Quantile Periodogram or Spectral Estimate |
| qspec.lw | Lag-Window Estimator of Quantile Spectrum and Cross-Spectrum (QSPEC) |
| sqdft | Spline Quantile Discrete Fourier Transform (SQDFT) |
| sqr.fit | Spline Quantile Regression (SQR) |
| tqr.fit | Trigonometric Quantile Regression (TQR) |
| tsqr.fit | Trigonometric Spline Quantile Regression (TSQR) |