P9X (codes to use from the start of the tax year)
Repayment Claim for Non-Residence in the UK (R43)
Repayment Claim for Tax deducted from Savings and Investments (R40)
Taxable Pay Tables (Manual Method)
Tables A (Pay Adjustment Tables)
CWG2 (Further guide to PAYE and NICs)
HMRC internal PAYE Manual
Some text in the Modal..