We consider the wave equation
\\begin{equation}
u_{tt}-a(x)u_{xx}=f,\\;\\;\\;(t,x)\\in(0,T)\\times(0,l),
\\end{equation}
with suitable initial and boundary conditions. Using an additional boundary measurement at $x=l$,
we study the identification of an unknown source term $f$. The analysis is
based on Carleman estimates for the wave operator; see \\cite{BY17}.
Funding: This research is funded by the Science Committee of the Ministry of Science and Higher Education of the
Republic of Kazakhstan (Grant No. AP23485971).

\\begin{thebibliography}{6}
\\bibitem{BY17} M. Bellassoued, M. Yamamoto. Carleman Estimates and Applications to Inverse Problems
for Hyperbolic Systems, Springer, Cham, 2017.
\\end{thebibliography}