Which is correct Dr. or Dr? [duplicate]

The Oxford Learners' Dictionary says:

Mr abbreviation (British English)
(also Mr. North American English, British English)

While the Oxford Learner's Dictionary of American English just states:

Mr. abbreviation

and has no entry for Mr without the period.

So I believe that both Mr and Mr. are acceptable in British English (even though Mr without period is preferred), while Mr. with period is mandatory in American English.

As an Italian, I prefer Mr without the period, because in school we were taught that the period following an abbreviation stood for "following letters omitted", but the r in Mr and in Dr is the last letter of Mister and Doctor, so no letter following "r" is omitted. I think that the British usage tends to conform to this "European" (Latin?) rule.

Both forms are acceptable. In modern British English, usually abbreviations are written without full stop marks. Full stops (US, 'periods') are normal in American English.

Dr (US, Dr.), Ltd (US, Ltd.), Kg (US, Kg.), Mr (US, Mr.), etc.

(From Micael Swan's PEU Chapter Abbreviations).