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Avargel, Y.; Cohen, I.. (2010). Undermodeling-Error Quantification for Quadratically Nonlinear System Identification in the Short-Time Fourier Transform Domain. , 58(12), 6052–6065. doi:10.1109/tsp.2010.2068296 
An interview with Sci-Hub Founder Alexandra Elbakyan,Who exactly should pay for academic research