Pengaruh umur, depresi dan demensia terhadap disabilitas fungsional lansia di PSTW Abiyoso dan PSTW Budi Dharma provinsi D.I. Yogyakarta: adaptasi model sistem Neuman = Influences of age, depression and dementia on the elderly functional disability at PSTW Abiyoso and PSTW Budi Dharma Province D.I. Yogyakarta: adapting the Neumann systems model