OpenOffice Writer can read WordPerfect 5.1 documents, as can Microsoft Word. Now if you can find something that can read Volkswriter Scientific documents, then I'll be impressed.
If the codes are badly translated Wordstar to Wordperfect, then I don't know. I don't have any Wordstar files to check...nor a copy of Wordstar. Or, unfortunately, Volkswriter Scientific.. but that's another story