rule 2A of point of taxation rules 2011

rule 2A date of payment
Point of taxation is earlier of
a) date on which payment is entered in books of accounts
or
b) date on which payment is credited in Bank account of person liable to pay tax

my query is for a) part- payment is entered in books account of service reciver or when service provider receive the receipt and he recorders.

whose books are to be considered service provider or service reciver?