我想通过以下方式在 Springer 期刊论文中添加一些引用，但始终不起作用。即：？ ？
Tex 文件
\RequirePackage{fix-cm}
%
%\documentclass{svjour3} % onecolumn (standard format)
%\documentclass[smallcondensed]{svjour3} % onecolumn (ditto)
\documentclass[smallextended]{svjour3} % onecolumn (second format)
%\documentclass[twocolumn]{svjour3} % twocolumn
%
\smartqed % flush right qed marks, e.g. at end of proof
%
\usepackage{graphicx}
\usepackage{natbib}
\begin{document}
\citep{Hvala}, \citep{Birkenmeier}
\bibliographystyle{spbasic}
\bibliography{litera} % name your BibTeX data base
\end{document}
% end of file template.tex
Bib 文件
@article{Hvala,
author = {Hvala, B.},
title = {Generalized derivations in rings},
journal = {Comm. Algebra},
volume = 26,
pages = {1147--1166},
year = 1998,
}
@inproceedings{Birkenmeier,
author = {Birkenmeier, G. F. and Heatherly, H. E. and Lee, E. K.},
title = {Completely prime ideals and radicals in Near-rings},
booktitle = {Proceedings of Near-rings and Near-Fields},
publisher = {Kluwer},
year = 1995,
pages = {63--73},
editor = {Fong, Y. and others},
}
提前谢谢您！