citation() command doesn't work in R.3.1.1

citation()

Error: $ operator is invalid for atomic vectors
In addition: Warning message:
In packageDescription(pkg = package, lib.loc = dirname(dir)) :
  no package 'base' was found

sessionInfo()

R version 3.1.1 (2014-07-10)
Platform: x86_64-w64-mingw32/x64 (64-bit)

locale:
[1] LC_COLLATE=Norwegian (Bokm?l)_Norway.1252
[2] LC_CTYPE=Norwegian (Bokm?l)_Norway.1252
[3] LC_MONETARY=Norwegian (Bokm?l)_Norway.1252
[4] LC_NUMERIC=C
[5] LC_TIME=Norwegian (Bokm?l)_Norway.1252

attached base packages:
[1] stats     graphics  grDevices utils     datasets  methods   base

loaded via a namespace (and not attached):
[1] tools_3.1.1

Sys.getlocale()

[1] "LC_COLLATE=Norwegian (Bokm?l)_Norway.1252;LC_CTYPE=Norwegian
(Bokm?l)_Norway.1252;LC_MONETARY=Norwegian
(Bokm?l)_Norway.1252;LC_NUMERIC=C;LC_TIME=Norwegian
(Bokm?l)_Norway.1252"