I often see e.g. used by non-native English speakers in the middle of a sentence like this:
Along with custom software, our services include e.g. consulting, integration, auditing and networking.
We have more experience of this, and especially e.g. complete solutions are our specialty.
Now e.g. is an abbreviation Latin exempli gratia, meaning for example.
But this usage sounds a bit unnatural to my ear. They are using e.g. where I would expect to find for example. But to me, e.g. isn't quite a drop-in replacement for for example, and the rule I have in my head is that the part of the sentence before e.g. needs to be a complete sentence, that the e.g. part is almost parenthetical.
For example, "Along with custom software, our services include" and "We have more experience of this, and especially" are not full sentences on their own.
This one looks fine to me:
I like citrus fruits, e.g., tangerines, lemons, and limes.
Because "I like citrus fruits" works as a complete sentence.
A similar thing applies to i.e. ("that is" – id est).
I've tried searching for guidance that says if this a rule of the English but have been unable to find anything explicit other than examples of this second form.
What are the rules in English for using e.g. and i.e. in the middle of a sentence?
Why can't e.g. (and i.e.) be used as drop in replacements for for example (and that is)?
Are there any reputable references for this rule?