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\begin{document}
\begin{LTR}
\begin{center} 
\begin{tabular}{ | m{4cm} |  m{5cm} | m{3cm} |} 
\hline
  FDIA research & Categories & References  \\ \hline
Teoretical researches on constructing a valid FDIA   & Construct a valid FDIA under certain constraints                    & [10] [12] [14] [15] [16] [17]    \\  \cline{2-3}
                                                                              & Construct a valid FDIA with incomplete information of matrix  & [18] [9] [20] [21]                    \\ \cline{2-3}
                                                                              & Construct a valid FDIA with topology being falsified                & [22] [28] [30]                           \\\cline{2-3}
                                                                              &Construct a valid FDIA under AC power flow model                  &    [23] [24] [25]                         \\ \hline 
Application reseraches on the impacts of FDIAs        & Aconomic Attack                                                                    & [26] [27] [28] [29] [30]              \\ \cline{2-3}
                                                                              &Load redistribution attack                                                       & [31] [32]                                      \\ \cline{2-3}
                                                                              &Energy decieving attack                                                          &[33]                                               \\ \hline 
Defense strategies against FDIAs                             & protect a set of basic measurments                                        &[10] [14] [34] [35]                          \\ \cline{2-3}
                                                                              &PMU-based Protection                                                             &[36] [37] [38] [39]                           \\\cline{2-3}
                                                                              & other ways of defending against FDIA                                     &[40] [41] [42] [43] [44] [45] [46]    \\\hline 
 \end{tabular} 
 \end{center} 
\end{LTR} 

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