The occupational burnout of mental health nurses in selected European countries: a meta-analysis of research studies using the MBI questionnaire - Łopatkiewicz, Aleksandra; Mańk, Michalina; Mikulski, Jantoni; Woynarowska-Sołdan, Magdalena; Krzych-Fałta, Edyta (Medical Studies/Studia Medyczne, 2022)