Yes, my fault, example was wrong, but this works:
<a href="https://www.ncbi.nlm.nih.gov/pubmed/27895593/">1</a>, <a href="https://www.ncbi.nlm.nih.gov/pubmed/22134706">2</a>
no space between 1 and 2
turn off html-compression – everything is ok, space is there
