Cleaning validation

The limit of recovery on ss plate in residue analysis is given as 70-130. Is it reference of any guideline? If yes, i need a reference of the guideline if anyone have

Please note that following,

9.3.2. There should be evidence that samples are accurately recovered (in cleaning validation Analytical method validation)
For example, a recovery of > 80% is considered good, > 50% reasonable
and < 50% questionable.

Reference: WHO Guidelines -WHO EXPERT COMMITTEE ON SPECIFICATIONS FOR
PHARMACEUTICAL PREPARATIONS
TRS 937, Appendix 3-Cleaning validation