BibDesk MultiMarkdown export template. Put into `~/Library/Application Support/BibDesk/Templates` and activate in settings to use.--- From http://zettelkasten.de/bibliography-zettelkasten/

markdownTemplate.txt

<$publications>
[#<$citeKey/>]: <$authors.name?>
<$authors.name.stringByRemovingTeX.@componentsJoinedByCommaAndAnd/><?$authors.name?><$editors.name.stringByRemovingTeX.@componentsJoinedByCommaAndAnd/> (Hrsg.)
</$authors.name?>
<$fields.Year?> (<$fields.Year/>)</$fields.Year?>:  _<$fields.Title.stringByRemovingTeX/><$fields.Subtitle?>. <$fields.Subtitle.stringByRemovingTeX/></$fields.Subtitle?>_<$pubType=article?>
, <$fields.Journal/><$fields.Number?> <$fields.Number/></$fields.Number?>, <$fields.Year/>, Vol. <$fields.Volume/>, S. <$fields.Pages/><?$pubType=incollection?>
, in: <$fields.Booktitle/><$fields.Address?>, <$fields.Address/>: <$fields.Publisher?><$fields.Publisher/></$fields.Publisher?><?$fields.Address?>
  <$fields.Publisher?>, <$fields.Publisher/></$fields.Publisher?>
</$fields.Address?>
<?$pubType?>
<$fields.Address?>, <$fields.Address/>: <$fields.Publisher?><$fields.Publisher/></$fields.Publisher?><?$fields.Address?>
  <$fields.Publisher?>, <$fields.Publisher/></$fields.Publisher?>
</$fields.Address?>
</$pubType?>.
</$publications>

Update 2014-01-19: add conditions to fields which sometimes aren't present so the markup doesn't get cluttered too bad.

Update 2015-08-27: Remove BibDesk links. Sound nice but get on my nerves too often.