>>> "Eric" == Eric S Fraga <esflists@gmail.com> writes:

   > On Thursday, 13 Dec 2018 at 11:55, Uwe Brauer wrote:
   >> That is for babel. That is I have an org file, which contains matlab and
   >> latex for the documentation. So I want to cite a reference. There is no
   >> problem with citep if I don't have the latex in a src block. 
   >> 
   >> However as I said the fortification is much nicer if I put latex in a
   >> src block.

   > Yes but my point is that the line that has the citep: link is org syntax
   > and should therefore not be in the LaTeX src block.  Keep the equation
   > in the src block but take that line to past the end of the block.

Oops, you are right and I am wrong, thanks.

BTW I just saw  mail from Nick in which he states 

> Why don't you use <C-c C-,>? It turns a region into a source block.

In which org version. What command is bound to C-c C-,

My version seems not to have it. (Master from last July, I think).