We all know that the full stop is used at the end of a sentence (anyone who hasn’t known this is needs special training). Full stop should indicate, in fact, that the sentence has come to a stop. Yet too often we come across letters that start like this:
“Referring to your letter of the 30th September.”
This collection of words is not a sentence, and after the full stop the reader is left floundering.
After “September” there should be a comma, followed by the noun or pronoun attached to the present participle “Referring”. A correct construction would thus consist of something like this:
“Referring to you letter of the 30th September, I am happy to say that your work shall be edited.”
An incorrect construction would be:
“Referring to your letter of the 30th September, your work shall be edited.”
This means, quite absurdly, that your work has been referring to your letter.