[OS X TeX] undefined control sequence error

[Mark Eli Kalderon]

Very curious. I get the following error in my log file:

[2] [3]
./EpistemicRelativism.tex:118: Undefined control sequence.
l.118 ...ropositions of much the same type. \citep
                                                   [85--6]{Boghossian: 
2006fk}
The control sequence at the end of the top line
of your error message was never \def'ed. If you have
misspelled it (e.g., `\hobx'), type `I' and the correct
spelling (e.g., `I\hbox'). Otherwise just continue,
and I'll forget about whatever was undefined.

./EpistemicRelativism.tex:123: Undefined control sequence.
l.123 ...dgments about what justifies what. \citep
                                                   [86]{Boghossian: 
2006fk}
The control sequence at the end of the top line
of your error message was never \def'ed. If you have
misspelled it (e.g., `\hobx'), type `I' and the correct
spelling (e.g., `I\hbox'). Otherwise just continue,
and I'll forget about whatever was undefined.

Why would `\citep` be an undefined control sequence? I get the same  
error with `\citet` `\cite` and a few other variants that I tried. I  
am running the last version of gwtetex and have never encountered  
such a thing before. Any thoughts would be greatly appreciated.  
Thanks in advance. All the best, Mark

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