Vera Angelova, Sensitivity of the nonlinear matrix equation -- Adjoint State Optimization Algorithm for Prediction of Honeybee Population Losses -- Study of time series connected to an innovative window heat transfer system -- Coefficient Identification for SEIR Model and Economic Forecasting in the Propagation of COVID-19 -- Recovering the Time-Dependent Volatility and Interest Rate in European Options from Nonlocal Price Measurements by Adjoint Equation Optimization -- Comparison of four classification methods on small-sample-size synthetic RNA-seq data -- Sensitivity Analysis of a Large-Scale Air Pollution Model by Using Effective Stochastic Approaches -- Two-Way Intuitionistic Fuzzy Analysis of Variance for COVID-19 Cases in Europe by Season and Location Factors -- A Generic Nonlinear Evolution Equation of Magnetic Type I. Reductions.