BibTeX, biblatex and biber ⇒ My reference is driving me crazy!

[nouna20]

hey fellow latex users
I am relatively new to latex, so please excuse any stupidity or obvious mistakes.
my basic concern is that my references show up in pdf like [?] and I got the typical message Citation 'Tand99' undefined on input.
N.B I can see the reference line in the last page of my pdf
here is some informations, I using winEdt 9.0.
when I compile my file I run .tex first then .bib then .tex twice.
here is a glimpse of my doc

Code: Select all

\documentclass[11pt,a4paper,oneside]{book}
\usepackage[T1]{fontenc}     
\usepackage[latin1]{inputenc} 
\usepackage[francais]{babel}
\selectlanguage{francais}     
                              
\usepackage{graphicx,multicol,color}
\usepackage{amssymb}  
\usepackage{multicol} {x}...\end{multicols}
\usepackage{enumerate}
\usepackage[french]{minitoc}
\setcounter{minitocdepth}{4}
\usepackage{chapterbib}
\usepackage{bibunits}   

\begin{document}

bonjour le monde \cite{Tand99}

\bibliographystyle{plain}
\bibliography{biblio_chap2,biblio_chap1}

\end{document}

and here is the bibtex

Code: Select all

@Article{Tand99,
 title = {A review of vibration and acoustic measurement methods for the detection of defects in rolling element bearings},
 author = {N. Tandona and A. Choudhury},
 journal = {Tribology International},
 volume* = { 32},
 year = {1999},
 pages* = {469–480},
}

I would appreciate your help! I am really desperate

[Johannes_B]

Hi and welcome,

can you show us the contents of your blg file? It should be in the same folder with your tex and bib. You might need to toggle file endings on with Windows.