I want to find position start and end of pattern on my text.

I use following code:

```
Pattern _pat=Pattern.compile("20.  Eslaminejad MB, Nikmahzar A, Piriea A. The structure   of "
+"Human Mesenchymal Stem Cells differentiated into cartilage in micro mass culture   system. Yakhteh 2006, 8(3): "
+"162-171.");

Matcher _match=_pat.matcher("19.  Eslaminejad  MB,  Eftekhari-Yazdi  P.   Mesenchymal  stem "
 +"cells: In vitro differentiation among bone and cartilage cell "
+"lineages. Yakhteh. 2007; 9(3): 158-169."
+"20.  Eslaminejad MB, Nikmahzar A, Piriea A. The structure of "
+"Human Mesenchymal Stem Cells differentiated into cartilage in micro mass culture     system. Yakhteh 2006, 8(3): "
+"162-171."
+"21.  Pioletti  DP,  Montjovent  MO,  Zambelli  PY,  Applegate  L. "
+"Bone tissue engineering using foetal cell therapy. Swiss "
+"Med Wkly. 2006 ; 136(35-36): 557-560.");

    while(_match.find()){
       System.out.println(_match.start());
       System.out.println(_match.end());
    }

```

Unfortunately, the pattern is not finding the string in my text.