引用不能包含数字？

Question

我正在生成我的论文但我的参考文献无法显示。

论文示例部分：

....conductive inks ~\cite{narita1991method} i.e.....

我有一个.bib文件并且\bibliography{XXX.bib}包含在内。

日志文件给了我这个，我不明白：

Introduction.tex, line 4
Use of \@citex doesn't match its definition.
\reserved@c ->\@tempswafalse \@citex ,
                                      []
l.4 ...his space including conductive inks ~\cite{
                                                  narita1991method} i.e. pai...
If you say, e.g., `\def\a1{...}', then you must always
put `1' after `\a', since control sequence names are
made up of letters only. The macro here has not been
followed by the required stuff, so I'm ignoring it.

有人知道这个问题吗？我是 LaTeX 新手，这是我的第一篇论文，所以这可能是一个愚蠢的错误，但我找不到问题所在。