::::::No, you only provided the author's surname and page number in the Fenni article, this is insufficient. You should follow the guide WP:CITE  for all the references in that article and all other articles for that matter. Yes, Whitaker concludes in the paper you found:  "On the other hand there is no firm evidence to suggest that they were any other ethnic group, just as there is no precise geographical location to which they can be ascribed.". He goes on to quote Finnish-American historian Wuorinen: "The obvious fact is, however, that Tacitus' mention of the "Fenni" must be dismissed as devoid of substance and meaning". Therefore, based upon this conclusion, the Fenni should be left off that map entirely.