Topic Discovery on Farsi, English, French, and Arabic Tweets Related to COVID-19 Using Text Mining Techniques. - Hamoon Jafarian; Mahin Mohammadi; Alireza Javaheri; Makram Sukarieh; Mohsen Yoosefi Nejad; Abbas Sheikhtaheri; Mehdi Hosseinzadeh 001; Elaheh Momeni-Ortner; Reza Rawassizadeh (dHealth, 2021)