[O] Tagging

[Florian Blank]

Hallo,

I'm quite new in org-mode. So I'm sorry to ask maybe an easy question, i 
absolutly do not find the solution for my problem. Even if I'm thinking, that 
org-mode ist the most sympatic and efficent way to work for me. But to the 
problem.

I want to use org-mode to organize excerpts. So my biggest Problem at the 
moment si, 

a) how to sum up multiple files und subfolders in an (root-)folder for a search 
on the tags, (and produce an file with an output)

b) how to extract the used tags of an given root-folder to a list
(buffer, file)

By the way: Not realy a big question to me at the moment, but I was wondering 
if der is any possibillity to handle bibtex files (*.bib)
like

@BOOK{Metaphysik_Rapp_1996,
  title = {Aristoteles Metaphysik, Die Substanzbücher {(Z,} Ē, {TH)}},
  publisher = {Akademie Verl.},
  year = {1996},
  author = {Christof Rapp},
  address = {Berlin},
  isbn = {9783050028651},
  keywords = {Metaphysik, Aristoteles, Substanz, ousia},
  lccn = {0000},
  owner = {schlaubi},
}

For example, that it ist possible to include in an tag-search the values of
 "keywords = {xxx}" of an given bibtex-file (database-file).

Thank you for your time,

Florian Blank.