July/August 2017: Volume 18 Number 7/8 10 August 2017. Related: PDFs. Two PDF versions are available for HTB. HTB July-Aug 2017e 1 column (PDF) 900 Kb A single column layout that is easier to read on tablets and other hand held devices. HTB July-Aug 2017e 2 column (PDF) 1.1 MB A two-column layout version that is easier to read if you are printing a paper copy.