1. WERTHER International “Electromechanical, two-column lift 254 S/4” Manual v. 09.09 Werther International POLSKA;Search in Google Scholar
2. 254 S/4 car lift advertisement – www.wertherint.com (13.07.2019);Search in Google Scholar
3. Office of Technical Inspection – https://www.udt.gov.pl/naprawy-i-modernicazje (13.07.2019);Search in Google Scholar
4. Ph.D., Eng. M. Jankowski “Zabezpieczenia w podnośnikach samochodowych” [Safeguards in Car Lifts]Search in Google Scholar
5. www.werther.pl/images/pisza/zabezpieczenia_w_podn_sam.pdf.Search in Google Scholar