Looking through twitter today I came across this tweet that says:
加拿大前六个部长上白皮书，要求释放王炳章 Six former Canadian ministers call for release of jailed Chinese dissident in open letter /via @globeandmail
The original article is in English, where they use the term "open letter." The Chinese translation is seeming just from Wang Bingwu where he rendered it as "白皮书."
This translation doesn't make much sense to me, as 公开信 is a perfectly common 1-to-1 translation for "open letter." And 白皮书 is just a translation of white paper. But, perhaps there is something to this that I am missing.
Is "白皮书" a good translation of "open letter"?