The publishing and editorial teams would like to thank the following, for their invaluable service as 2021 reviewers for this journal. We are very grateful for the contributions made. With their help, the journal has been able to publish such high-quality articles:
| Abellana, Dharyll Prince |
| Adnan, Md Nasim |
| Agarwal, Isha |
| Ahammad, Nur |
| Al Dulaimi, Ali |
| Al Rahhal, Mohamad M. |
| Al-Janabi, Samir |
| Al-Okaily, Aws |
| Alarab, Ismail |
| Alemu, Getaneh |
| Alexandridis, Georgios |
| Aljohani, Naif |
| Alnawas, Anwar |
| AlQenaei, Zainab |
| Alva Manchego, Fernando |
| Alzubi, Jafar A. |
| An, Jingmin |
| Arunkumar, Anjana |
| Augustine, Susan |
| Ayan, Enes |
| Ayubi, Peyman |
| Badenes-Olmedo, Carlos |
| Banerjee , Buddhananda |
| Basilio, Marcio |
| Berkani, Lamia |
| Birant, Derya |
| Bogdanović, Zorica |
| Borovič, Mladen |
| Brahimi, Belkacem |
| Cambria, Erik |
| Can, Ozgu |
| Castillo de Mesa, J. |
| chandwani, Gunjan |
| Chang, Temin |
| Chang, Chung |
| Chang, Kuo-Chien |
| Chapman, Age |
| Chen, Chenglizhao |
| Chen, Li-Pang |
| Chen, Liang-Chu |
| Chen, Mu-Chen |
| Chen, Wen-Kuo |
| Chen, Yen-Liang |
| Chen, Yewang |
| Cheng, Gong |
| Cheng, Lei |
| Chicaiza, Janneth |
| Chiou, Yu-Chiun |
| Choudhary, Chaitali |
| Colace, Francesco |
| Cosman, Pamela |
| Cox, Andrew |
| Dai, Tian-Shyr |
| Dalila K.A., Nur |
| Danesh, Farshid |
| Dash, Rasmita |
| Debruyne, Christophe |
| Deng, Wu |
| Devidaspergad, Namdev |
| Dodero, Juan-Manuel |
| Dong, Shi |
| Dressler, Virginia |
| Du, Mingjing |
| Dunne, Jonathan |
| Elrashidy, Mohamed |
| Evans, Richard |
| Fang, Ming |
| Fensel, Anna |
| Ferreras-Fernández, Tránsito |
| Figueroa, Alejandro |
| Forouzandeh, Saman |
| Friston, Karl |
| Gadi, Manoel |
| Gajmal, Yogesh M |
| García-Peñalvo, Francisco |
| García, María N. Moreno |
| Gervais, Arthus |
| Giese, Martin |
| Glavee-Geo, Richard |
| Gonzalez Garcia, Lino |
| Goswami, Anuradha |
| Gupta, Brij B. |
| Halbhavi, Sadashiv |
| Heidari, Maryam |
| Hong, Danfeng |
| Hsiao, Wen-Feng |
| Hsiao, Yu-Hsiang |
| Hsieh, Chin-Yu |
| Hsu, Y.-F |
| Huang, Fang |
| Huang, Qunying |
| Huda, Miftachul |
| Ibtissem, Gasmi |
| Iglesias, Patricia |
| Jadhav, Amolkumar |
| Javed, Abdul Rehman |
| K G, Nandha Kumar |
| Kaleli, Cihan |
| Kalender, Murat |
| Karetsos, Sotiris |
| Kaya, Ceren |
| Khan, Hassan |
| Kilimci, Zeynep Hilal |
| Kim, Byunghoon |
| Klímek, Jakub |
| Kong, Zhi |
| Kratochvil, Renate |
| Kumar, Manoj |
| Kwon, Hyuk-Yoon |
| Labus, Aleksandra |
| Laddi, Amit |
| Lai, Hung-Neng |
| Lai, Kuan-Ting |
| Lan, Guipeng |
| Lan, Le Thi |
| Lange, Matthias |
| Lawlor, Aonghus |
| Le, Nguyen Quoc Khanh |
| Lee, Changro |
| Lee, Patrick Chang Boon |
| Lee, Wen-Li |
| Leporati, Alberto |
| Li, Quan |
| Li, Shudong |
| Li, Xiang |
| Li, Xiaochao |
| Li, Zhuopeng |
| Lim, Weng Marc |
| Lin, Chaun-Jie |
| Liu, Duen-Ren |
| Liu, Fanzhen |
| Liu, Guanjun |
| Liu, Peng |
| Liu, Yan |
| Liu, Yi-Hung |
| Liu, Yipeng |
| Lo, Chu-Pin |
| Lo, Jian-Ming |
| López-Barbosa, Rutilio |
| Lu, Chao |
| Ma, Shutian |
| Mariam, Komal |
| Mazzucchelli, Alice |
| Melen, Riccardo |
| Miguel Ángel, Sicilia Urbán |
| Mora-Cantallops, Marçal |
| Moradi, Mohammad |
| Mosca, Alessandro |
| Moschoyiannis, Sotiris |
| Mountantonakis, Michalis |
| Moya-Albor, Ernesto |
| Mu, Yashuang |
| Musulin, Jelena |
| Mylonas, Phivos |
| Nacer, Mohamed Ikbal |
| Nasfi, Rim |
| Nečaský, Martin |
| Nemati, Shahla |
| Ngueilbaye, Alladoumbaye |
| Nguyen, Dang |
| Nguyen, Thi My Binh |
| Nikolov, Nikolay |
| Ning, Xin |
| Oh, Hyo-Jung |
| Onan, Aytug |
| Orduña-Malea, Enrique |
| Pal, Anjan |
| Pandey, Saroj |
| Park, Eunil |
| Patel, Harshita |
| Pekovic, Sanja |
| Pereira, Valdecy |
| Perez, Beatrice |
| Pichappan, Pit |
| Pomp, André |
| Qu, Jian |
| Quang A, Dang |
| R, Cristin |
| Rajabi, Enayat |
| Ramachandran, R. |
| Rana, Dipti |
| Reddy K., Sudheer |
| Regulski, Krzysztof |
| Rousidis, Dimitris |
| Rowley, Jennifer |
| Şahin, Serap |
| Samaras, Loukas |
| Sanchez-Alonso, Salvador |
| Sandubete, Julio E. |
| Sautot, Lucile |
| Savi, Marco |
| Selvaraj, Geetha |
| Shafait, Faisal |
| Shah, Adnan |
| Sharma, Anuj |
| shuang, li |
| Singh, Archana |
| Singh, Sonika |
| Sinha, Atreyee |
| Son, Youngdoo |
| Soylu, Ahmet |
| Sun, Jiankai |
| Sun, Rui |
| Svátek, Vojtěch |
| Tabares-Soto, Reinel |
| Tan, Tony |
| Tayab, Usman Bashir |
| Thapaliya, Ananga |
| Tovanich, Natkamon |
| Trifan, Alina |
| Troussas, Christos |
| Troussas, Christos |
| Tsai, Kuo-Yu |
| Tu, Bing |
| Udanor, Collins |
| Vozel, Benoit |
| Vu, Hai |
| Vudragovic, Dusan |
| Wan, Xiaohui |
| Wang, Changbo |
| Wang, Chih-Hsuan |
| Wang, Gongming |
| Wang, Hei-Chia |
| Wang, Jiaqi |
| Wang, Kewen |
| Wen, Chih-Hao |
| Williams, Lowri |
| Wu, Jianpeng |
| Xiao, Changjiang |
| Xiao, Jun |
| Xue, Yu |
| Xueyi, Ye |
| Yang, Tao |
| Yang, Yue |
| Yin, Hong |
| Yoo, Donghee |
| Yu, Hui |
| Zhang, Chengzhi |
| Zhang, HuaXin |
| Zhang, Qingchuan |
| Zhang, Zhuo |
| Zhang, Zi-Ke |
| Zheng, Chunhou |
| Zhou, Baifan |
| Zhou, Funa |
| Zorbas, Dimitrios |