## 3 Results and Discussion
### Analysis of Extracted Data
\begin{table}
\begin{tabular}{c c c c c c c} \hline \hline
**Reference** & **Test Data** & \
\begin{tabular}{c} **COVID-19** \\ **Positive** \\ \end{tabular} &
\begin{tabular}{c} **Pneumonia/Other** \\ **Infection** \\ \end{tabular} & **Healthy** & **Total** & **Sources/Links** \\ \hline
[35] & \
\begin{tabular}{c} Chest X-ray \\ CT Images \\ \end{tabular} & 50 & *NA & 50 & 100 &
\begin{tabular}{c} [[https://github.com/ieee802](https://github.com/ieee802)]([https://github.com/ieee802](https://github.com/ieee802)) \\ 3/covid-chestray-dataset \\ \end{tabular} \\
[35] & \
\begin{tabular}{c} Chest X-ray \\ CT Images \\ \end{tabular} & 50 & *NA & 50 & 100 &
\begin{tabular}{c} [[https://www.kaggle.com/](https://www.kaggle.com/)]([https://www.kaggle.com/](https://www.kaggle.com/)) \\ paultimothymooney/chest- \\ xray \\ \end{tabular} \\ \hline
[36] & \
\begin{tabular}{c} Chest X-ray \\ \end{tabular} & 284 & 657 & 310 & 1251 &
\begin{tabular}{c} [[https://github.com/ieee802](https://github.com/ieee802)]([https://github.com/ieee802](https://github.com/ieee802)) \\ 3/covid-chestray-dataset \\ \end{tabular} \\
[37] & \
\begin{tabular}{c} Chest X-ray \\ \end{tabular} & 250 & 2753 & 3520 & 6523 &
\begin{tabular}{c} [[https://github.com/](https://github.com/)]([https://github.com/](https://github.com/)) \\ [PERSON]/COVID-19 \\ [[https://www.kaggle.com/](https://www.kaggle.com/)]([https://www.kaggle.com/](https://www.kaggle.com/)) \\ paultimothymooney/chest- \\ xray \\ \end{tabular} \\ \hline
[37] & \
\begin{tabular}{c} Chest X-ray \\ \end{tabular} & 250 & 2753 & 3520 & 6523 &
\begin{tabular}{c} [[https://github.com/](https://github.com/)]([https://github.com/](https://github.com/)) \\ 3/covid-chestray-dataset \\ \end{tabular} \\
[38] & \
\begin{tabular}{c} Chest X-ray \\ \end{tabular} & 274 & 2051 & 1341 & 3666 &
\begin{tabular}{c} [[https://www.kaggle.com/](https://www.kaggle.com/)]([https://www.kaggle.com/](https://www.kaggle.com/)) \\ tawsfirurrahman/covid19- \\ radiography-database \\ \end{tabular} \\
[39] & \
\begin{tabular}{c} Chest X-ray \\ \end{tabular} & 274 & 2051 & 1341 & 3666 &
\begin{tabular}{c} [[https://github.com/](https://github.com/)]([https://github.com/](https://github.com/)) \\ radisgruby-figure1-COVID-chestray-dataset \\ \end{tabular} \\
[26] & \
\begin{tabular}{c} CT Images \\ \end{tabular} & 1296 & 1735 & 1325 & 4356 &
\begin{tabular}{c} [[https://github.com/](https://github.com/)]([https://github.com/](https://github.com/)) \\ bkong99/COVNet \\ \end{tabular} \\ \hline
[39] & \
\begin{tabular}{c} CT Images \\ \end{tabular} & 510 & 510 & *NA & 1020 &
\begin{tabular}{c} Alexion, Toshiba Medical \\ System, Japan \\ \end{tabular} \\ \hline
[11] & \
\begin{tabular}{c} Chest X-ray \\ \end{tabular} & 250 & 500 & 1000 & 1750 &
\begin{tabular}{c} [[https://github.com/](https://github.com/)]([https://github.com/](https://github.com/)) \\ 3/COVID-chestarray-dataset \\ \end{tabular} \\ \hline
[40] & \
\begin{tabular}{c} CT Images \\ \end{tabular} & 219 & 224 & 175 & 618 &
\begin{tabular}{c} Hospital of Zhejiang \\ University \\ Hospital of Wenzhou \\ Hospital of Wenling \\ \end{tabular} \\ \hline
[41] & \
\begin{tabular}{c} CT Images \\ \end{tabular} & 313 & *NA & 229 & 542 &
\begin{tabular}{c} Union Hospital Tongji \\ Medical College, Huazhong \\ University of Science and \\ Technology, China. \\ \end{tabular} \\ \hline
[42] & \
\begin{tabular}{c} CT Images \\ \end{tabular} & 325 & 740 & *NA & 1065 &
\begin{tabular}{c} Xi'an Jiaotong University \\ First Affiliated Hospital \\ Nanchang University First \\ Hospital \\ Xi’an No.8 Hospital of Xi’an Medical College, China \\ \end{tabular} \\ \hline
[43] & \
\begin{tabular}{c} CT Images \\ \end{tabular} & 777 & **NS & 708 & 1485 &
\begin{tabular}{c} The Third Affiliated Hospital \\ and Sun Yat-Sen Memorial \\ Hospital, Sun Yat-sen \\ University Guangzhou \\ Renmin Hospital of Wuhan \\ University, China \\ \end{tabular} \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Summary of the datasets used in the selected papers. _Appl. Sci._**2021**, _11_, 3414