1. ‘Vickers’—Industrial Hydraulics Manual, Second edition, 1989
2. ‘The systematic approach to contamination control’—Vickers Fluid Power System, pp. 6–7
3. NAS 1638—National Aerospace Standard
4. ISO 4406-1999 (E) Hydraulic fluid power—fluid methods for counting the level of contamination by solid particle
5. SAE AS 4059—Aerospace Fluid Power-Cleanliness Classification for Hydraulic Fluid