“Measuring activity engagement in old age: An exploratory factor analysis,” by Calum Marr, Eleftheria Vaportzis, Malwina A. Niechcial, Michaela Dewar, and Alan J. Gow (PLoS ONE 16(12): e0260996. doi.org/10.1371/journal.pone.0260996, XML, HTML, and .pdf format, 14p.).
journals.plos.org/plosone/article?id=10.1371/journal.pone.0260996
