PT Journal AU Machalkova, L Reiterova, E Satekova, L Sevcikova, B Sikorska, L TI Sleep of nurses in the context of diurnal preference and the shift work SO Profese Online PY 2021 BP 11 EP 19 VL 13 IS 2 DI 10.5507/pol.2020.012 DE Composite scale of morning and evening types; circadian rhythm; chronotype; morning and night shift; sleep quality ER