Convert WKS to PDF

It looks that some older versions of Office actually supported WKS formnat, which would be the easiest way how to achieve export to PDF. Microsoft Excel 2010 and later most likely cannot open or work with WKS spreadsheets, regardless if they come from Microsoft Works or old Lotus 1-2-3. 

Open source programs from the Libre Office and OpenOffice.org bundles still support WKS format and can be used to successfully for wks to pdf conversion. Corel Quattro Pro supposedly also still have support for WKS format.