Adult mortality before and during the first wave of COVID-19 pandemic in nine communities of Yemen: a key informant study oleh Mervat Alhaffar, Huda Basaleem, Fouad Othman, Khaled Alsakkaf, Sena Mohammed Mohsen Naji, Hussein Kolaise, Abdullah K. Babattah, Yassin Abdulmalik Mahyoub Salem, Hannah Brindle, Najwa Yahya, Pasquale Pepe, Francesco Checchi