Adjoint polynomial formulas for nonlinear state-space realizationBelikov, Juri; Kotta, Ülle; Tõnso, MarisIEEE transactions on automatic control2014 / p. 256-261

Degree of Dieudonne determinant defines the order of nonlinear systemKotta, Ülle; Belikov, Juri; Halas, Miroslav; Leibak, AlarInternational journal of control2019 / p. 518-527 https://doi.org/10.1080/00207179.2017.1361042 Journal metrics at Scopus Article at Scopus Journal metrics at WOS Article at WOS

Extended observer form : simple existence conditionsKaparin, Vadim; Kotta, Ülle; Mullari, TanelInternational journal of control2013 / p. 794-803 : ill

Forward and backward shifts of vector fields : towards the dual algebraic frameworkMullari, Tanel; Kotta, Ülle; Bartosiewicz, Zbigniew; Pawluszewicz, Ewa; Moog, ClaudeIEEE transactions on automatic control2017 / p. 3029-3033 https://doi.org/10.1109/TAC.2016.2608718

Further results on identifiability of discrete-time nonlinear systemsNõmm, Sven; Moog, ClaudeAutomatica2016 / p. 69-74 : ill https://doi.org/10.1016/j.automatica.2016.01.054

Linearization by input-output injections on homogeneous time scalesCiulkin, Monika; Kaparin, Vadim; Kotta, Ülle; Pawluszewicz, EwaProceedings of the Estonian Academy of Sciences2014 / p. 387-397 https://artiklid.elnet.ee/record=b2707375*est

Observable space of the nonlinear control system on a homogeneous time scaleKaparin, Vadim; Kotta, Ülle; Wyrwas, MałgorzataProceedings of the Estonian Academy of Sciences2014 / p. 11-25 https://artiklid.elnet.ee/record=b2665198*est

On the finiteness of accessibility test for nonlinear discrete-time systemsSarafrazi, Mohammad Amin; Pawluszewicz, Ewa; Bartosiewicz, Zbigniew; Kotta, ÜlleInternational journal of control2021 / p. 2330-2336 https://doi.org/10.1080/00207179.2019.1706102 Journal metrics at Scopus Article at Scopus Journal metrics at WOS Article at WOS

On the properties of forward and backward shifts of vector fieldsKaldmäe, Arvo; Kaparin, Vadim; Kotta, Ülle; Mullari, Tanel; Pawluszewicz, EwaProceedings of the Estonian Academy of Sciences2022 / p. 314-325 https://doi.org/10.3176/proc.2022.4.02 Journal metrics at Scopus Article at Scopus Journal metrics at WOS Article at WOS

Relaxing realizability conditions for discrete-time nonlinear systemsKotta, Ülle; Schlahter, Kurt; Tõnso, MarisAutomatica2015 / p. 67-71 http://dx.doi.org/10.1016/j.automatica.2015.05.007

Transfer matrix and its Jacobson form for nonlinear systems on time scales : mathematica implementationBelikov, Juri; Kotta, Ülle; Leibak, AlarFull Papers : 18th International Conference on Process Control '11 : June 14-17, 2011, Tatransk Lomnica, Slovakia2011 / p. 141-146

Transformation of nonlinear discrete-time state equations into the observer form : extension to non-reversible caseMullari, Tanel; Kotta, ÜlleProceedings of the Estonian Academy of Sciences2021 / p. 235-247 https://doi.org/10.3176/proc.2021.3.03 Journal metrics at Scopus Article at Scopus Journal metrics at WOS Article at WOS

Transformation of nonlinear discrete-time state equations into the observer form : revisionMullari, Tanel; Kotta, ÜlleProceedings of the Estonian Academy of Sciences2023 / p. 1-5 https://doi.org/10.3176/proc.2023.1.01

Transformation of nonlinear discrete-time system into the extended observer formKaparin, Vadim; Kotta, ÜlleInternational journal of control2018 / p. 848-858 https://doi.org/10.1080/00207179.2017.1294264 Journal metrics at Scopus Article at Scopus Journal metrics at WOS Article at WOS

Transformation of nonlinear MIMO discrete-time systems into the extended observer formKaparin, Vadim; Kotta, ÜlleAsian journal of control2019 / p. 2208–2217 : ill https://doi.org/10.1002/asjc.1824 Journal metrics at Scopus Article at Scopus Journal metrics at WOS Article at WOS

Transformation of nonlinear state equations into the observer form : necessary and sufficient conditions in terms of one-formsKaparin, Vadim; Kotta, ÜlleKybernetika2015 / p. 36-58 http://dx.doi.org/10.14736/kyb-2015-1-0036