We thank the following reviewers for their contribution and support in 2021.

Nisar Ahmad

Pakistan

Erman Akkus

Turkey

John J. Araujo

Colombia

Zhaohui Bai

China

Mirza Rafi Baig

Dubai

Sudip Banerjee

India

Ebru Basaran

Turkey

Jiasheng Cao

China

Tianzhen Chen

China

Hongwei Cheng

China

Talha Bin Emran

Bangladesh

Yuchen Fan

China

Yinghong Feng

United States

Qi Feng

China

Janaina Fernandes

Brazil

Xinsheng Gu

China

Surampalli Gurunath

India

Darlan Gusso

Brazil

Chao Han

China

Noriko Hirai

Japan

Tahereh Hosseinabadi

Iran

Qing Huan

China

Zhen-peng Huang

China

Jia Huang

China

Zhenpeng Huang

China

Irina Ielciu

Romania

Tuo Ji

United States

Tom C Karagiannis

USA

Nicholas Kipshidze

USA

Weijun Kong

China

Xin Li

China

Boyu Li

China

Michael Liebman

United States

Michael N Liebman

USA

Peng Liu

China

Linsheng Liu

China

Lianxiang Luo

China

Rafiullah Baig Mirza

United Arab Emirates

Elsayed A Mohamed

Egypt

Saeed Mohammadi

Iran

Muhammad Nawaz

Saudi Arabia

Anna Pratima Nikalje

India

Amany Nofal

Egypt

Shuta Ohara

Japan

Lei Pei

China

Minhua Peng

China

Hakim Rahmoune

Algeria

Senthilkumar Rajagopal

India

Ali Saber

Netherlands

Celestino Sardu

Italy

Marco Sebastiani

Italy

Muhammad Shahid

Pakistan

Junping Shi

China

Rajesh Kumar Singh

India

Donglei Sun

China

Toshinori Takada

Japan

Massimo Tusconi

Italy

Srijayaprakash Babu Babu Uppada

USA

Yang Wang

China

Xiaokang Wang

China

Karol Wróblewski

Poland

Fan Wu

China

Wenrui Xie

China

Jianshe Yang

China

Guanjun Yang

China

Yikai Yu

China

Shi-Jun Yue

China

Apostolos Zarros

UK

Jianbin Zhang

China

Jinwei Zhang

UK

Xianbin Zhang

China

Wei Zhao

China

Tao Zheng

China

Lili Zhou

China