Johannes Handler Dimitar Ninevski Paul O'Leary Modelling Periodic Measurement Data Having a Piecewise Polynomial Trend Using the Method of Variable Projection. 1-8 2023 IECON https://doi.org/10.1109/IECON51785.2023.10312537 conf/iecon/2023 db/conf/iecon/iecon2023.html#HandlerNO23