For example, the arts and crafts sales website Etsy requires "vintage" items sold on their platform to be "at least 20 years old". "Vintage Items on Etsy". 18 October 2017.[permanent dead link]
Mueller, Shirley M. (2019). Inside the Head of a Collector: Neuropsychological Forces at Play. Seattle. ISBN978-0-9996522-7-5. OCLC1083575943.{{cite book}}: CS1 maint: location missing publisher (link)