PRE string definition was missing.

fnevgeny · fnevgeny · commit 32158c2b6051 · 2015-08-14T23:10:22.000-04:00
diff --git a/doc/facref.bib b/doc/facref.bib
@@ -11,6 +11,7 @@ @string(JPCRD
 @string(JQSRT = {J. Quant. Spect. Rad. Trans.})
 @string(MNRAS = {Mon. Not. R. Astron. Soc.})
 @string(PRA   = {Phys. Rev. A})
+@string(PRE   = {Phys. Rev. E})
 @string(PSCR  = {Phys. Scr.})
 @string(SOLP  = {Sol. Phys.})
 
