suffixes - -的 adjectives modifying nouns without な

Am I correct in thinking that these are ok without a na:

1) 印象的な事実
2) 印象的事実
3) 客観的な事実
4) 客観的事実

But these need a na?:

5) 明らかな事実

6) ＊?明らか事実
7) 簡単な事実
8) ＊?簡単事実

(From a quick look, Google results count seems to support this).

According to Daijirin, -teki should be making na-adjectives:

名詞に付いて、形容動詞の語幹をつくる。

But is it the case that these -teki-adjectives (and only they) accept dropping the na? If so, why is that? Influence from the original Chinese particle?

Is there any linguistic articles on this topic?

Answer

Matt Treyvaud answered my question elsewhere, so I'm posting his answer here.

• Yes, teki-words are unlike other na-adjectives in that they can modify nouns without a na. The Daijirin definition was incomplete. From the Nihon Kokugo Daijiten:

漢語について、直接、または「な」 をともなって連体修飾語として用いられるほか、形容動詞語幹として使われる。

• Contrary to what I proposed above, teki-words seem to be able to work as nouns, after all. A closer look on the web and Twitter found examples of teki-words followed by を or subject が. Again from the Kokugo Daijiten:

名詞、特に抽象的な意味を表わす漢語の名詞や体言的な語および句について、体言、または形容動詞語幹をつくる。

• And yes, this is due to influence from Chinese grammar, from where the morpheme was borrowed in the first place. But Japanese teki is a lot newer than I expected (de 的 isn't, after all, a Literary Chinese particle; that would be zhī 之). Turns out that teki-words are as recent as Meiji. In its early days, teki has even seen use as a general nominalizer:

＊文章新論〔１８８６〕〈坪内逍遙〉「予がいふ反訳文は今の新聞紙の文体をいふ也。『豈（あに）それ然らんや』的の文章、若しくは『アナ喧や静まらずや』的の文辞をいふなり」