https://wiiw.ac.at/economic-forecast-for-eastern-europe-the-worst-is-yet-to-come-n-570.html
https://www.boeckler.de/pdf/p_imk_report_139_2018.pdf
https://www.exact.com/benl/downloads/finance/whitepaper-cijfers-altijd-het-antwoord
https://www.persee.fr/doc/rfeco_0769-0479_1995_num_10_2_978