Thank you very much Paul. I am almost there. All that remains is that Xxxx. must appear is a list of valid abbreviations, otherwise the Roman conversion must not take place:

Eg. A sentence that reads: Vergelyk Hand. vii. 12, en die ook by v. 1.

"Hand." will appear in my list but "by" will not. So it needs to convert to:

Vergelyk Hand. 7:12 en ook by v. 1.

The way the code currently stand it will convert to:

Vergelyk Hand. 7:12 en ook by 5:1.