Question:
These unsung, yet worthy, vintages very often cost hardly any more than bottled mineral water.

Does it follow that "These antiques are worth more than what they cost."?
Answer:
it is not possible to tell

Question:
Look for silver filigree earrings and brooches, often in the form of flowers or butterflies.

Does it follow that "There are some earrings that are shaped like butterflies."?
Answer:
yes

Question:
Moreover, after Gerth's article the White House released a series of documents detailing the decision.

Does it follow that "The White House released a series of documents after Gerth's article."?
Answer:
yes

Question:
and so you know you could also apply the magazines toward that

Does it follow that "You already know exactly how this works, don't you?"?
Answer:
it is not possible to tell