accounting periods
...that United Kingdom corporation tax is charged with reference to accounting periods?
...that <a href="./United_Kingdom_corporation_tax" id="mwAZ4" rel="mw:WikiLink" title="United Kingdom corporation tax">United Kingdom corporation tax</a> is charged with reference to <b id="mwAZ8"><a href="./Accounting_period" id="mwAaA" rel="mw:WikiLink" title="Accounting period">accounting periods</a></b>?