\Refs

\ref\no 1
\by             Mophou~G.M.
\paper          Optimal control of fractional diffusion equation
\jour           Comput. Appl. Math.
\yr             2010
\vol            61
\issue          1 
\pages          68--78 
\endref
% DOI: 10.1016/j.camwa.2010.10.030.

\ref\no 2
\by             Tang~Q. and Ma~Q.
\paper          Variational formulation and optimal control
                of fractional diffusion equations with Caputo derivatives
\jour           Adv. Difference Equ.
\yr             2015
\vol            Article no.~283 
%\issue
\endref
% DOI: 10.1186/s13662-015-0593-5.

\ref\no 3
\by               Zhou~Z. and Gong~W.
\paper            Finite element approximation of optimal control problems 
                  governed by time fractional diffusion equation
\jour             Comput. Appl. Math.
\yr               2016
\vol              71
\issue            1 
\pages            301--318
\endref
% DOI: 10.1016/j.camwa.2015.11.014.

\ref\no 4
\by          Kilbas~A.A., Srivastava~H.M., and Trujillo~J.J.
\book        Theory and Applications of Fractional Differential Equations
\publaddr    Amsterdam, Boston, and Heidelberg
\publ        Elsevier
\yr          2006
\endref

\ref\no 5
\by          Butkovskii~A.G.
\book        Distributed Control Systems
\publaddr    New York
\publ        Elsevier
\yr          1969
\endref

\ref\no 6
\by             Sandev~T. and Tomovski~Z.
\paper          The general time fractional wave equation for a vibrating string
\jour           J.~Phys.~A: Math. Theoret. 
\yr             2010
\vol            43
\issue          5 
\pages          Paper ID~055204
\endref
 % DOI: 10.1088/1751-8113/43/5/055204.

\ref\no 7
\by             Agrawal~O.P.
\paper          Fractional variational calculus in terms of Riesz fractional derivatives
\jour           J.~Phys.~A: Math. Theoret.
\yr             2007
\vol            40
\issue          24
\pages          6287--6303
\endref
% DOI: 10.1088/1751-8113/40/24/003.

\ref\no 8
\by             Kubyshkin~V.A. and Postnov~S.S.
\paper          Time-optimal boundary control for systems 
                defined  by a~fractional order diffusion equation
\jour           Automation and Remote Control 
\yr             2018
\vol            79
\issue          5 
\pages          884--896
\endref
% DOI: 10.1134/S0005117918050090.


\endRefs