olink.doctitle — show the document title for external olinks?
When olinks between documents are resolved for print output, the generated text may not make it clear that the reference is to another document. It is possible for the stylesheets to append the other document's title to external olinks. For this to happen, two parameters must be set. The olink.doctitle parameter should be set to nonzero to enable this feature. And you should set the current.docid parameter to the document id for the document currently being processed for output. If an olink's targetdoc id differs from the current.docid, then the stylesheet can append the target document's title to the generated olink text.