An example with the natbib package.
Make a file called "biblio.bib" such as:
@book{Renardy,
Author = {M. Renardy and R. C. Rogers},
Edition = {Second},
Publisher = {Springer},
Title = {An Introduction to Partial Differential Equations},
Year = {2004}}
And your tex file:
\documentclass{article}
\usepackage{natbib}
\begin{document}
According to \citet{Renardy}, the amount of...
\bibliographystyle{plainnat}
\bibliography{biblio.bib}
\end{document}
The .bib file is especially easy to make with a program such as BibDesk.
The bibliographystyle (now plainnat) can be changed. Note that you need to typeset your file multiple times. Also the BibTex. In TexShop, under macros > Applescript there is a script called "Bibliography" that does the necessary typesets for you.
Also see: https://en.wikibooks.org/wiki/LaTeX/Bibliography_Management.
citetorcitep, with biblatex it would be\textcite. – Johannes_B Jul 10 '16 at 15:09natbibpackage,\citeshould produce a textual citation call-out, provided the bibliography style is capable of doing so. For sure,plaincannot produce textual citations, butplainnatcan. Please do tell us which bibliography style you use, and please indicate whether you use a citation management package such asciteornatbib. – Mico Jul 10 '16 at 15:16