https://www.epsu.org/sites/default/files/article/files/EPSU%20Report%20Outsourcing%20state_EN.pdf
https://www.imf.org/-/media/Files/Publications/DP/2022/English/POSRFEA.ashx
https://ukandeu.ac.uk/is-economic-output-an-accurate-measure-of-the-covid-19-impact/
https://www.smmt.co.uk/wp-content/uploads/sites/2/SMMT-Sustainability-Report-2018.pdf