Question

I got some problems with my patterns. Hope somebody could help me with this.

given a string

$string = Mutualism has been retrospectively characterised as ideologically situated between individualist and collectivist forms of anarchism.<ref>Avrich, Paul. ''Anarchist Voices: An Oral History of Anarchism in America'', Princeton University Press 1996 ISBN 0-691-04494-5, p.6<br />''Blackwell Encyclopaedia of Political Thought'', Blackwell Publishing 1991 ISBN 0-631-17944-5, p. 11.</ref> Proudhon first characterised his goal as a "third form of society, the synthesis of communism and property."<ref>Pierre-Joseph Proudhon. ''What Is Property?'' Princeton, MA: Benjamin R. Tucker, 1876. p. 281.</ref> Another is <ref name=rupert/>

I want to remove strings inside the &lt;ref&gt; (<ref name='something'></ref> or <ref></ref>) or remove the single ref tag <ref name='sss' />

after replacing the final out put should be :

Mutualism has been retrospectively
characterised as ideologically
situated between individualist and
collectivist forms of anarchism.
Proudhon first characterised his goal
as a “third form of society, the
synthesis of communism and property.”
Another is

my code doesn’t seem to work

$pattern1[] = "/&lt;ref[^\/]*\/&gt;/is"; //remove <ref name=something/>  
$pattern1[] = "/&lt;ref[^\/]*&gt;(.*?)&lt;\/ref&gt;/s";  //remove ref <ref>some text here</ref>
preg_replace($pattern1,"\n", $string);

instead it outputs :

Mutualism has been retrospectively
characterised as ideologically
situated between individualist and
collectivist forms of anarchism.
”Blackwell Encyclopaedia of Political
Thought”, Blackwell Publishing 1991
ISBN 0-631-17944-5, p. 11.</ref>
Proudhon first characterised his goal
as a "third form of society, the
synthesis of communism and
property." Another is

I guess it got caught up with the <br />

Answer 1

The Problem is that your first pattern is also matching

<ref>Avrich, Paul. ”Anarchist
Voices: An Oral History of Anarchism
in America”, Princeton University
Press 1996 ISBN 0-691-04494-5,
p.6<br />

[^\/]* matches the following

>Avrich, Paul. ”Anarchist Voices:
An Oral History of Anarchism in
America”, Princeton University Press
1996 ISBN 0-691-04494-5, p.6<br

the solution is to use /<ref(?:[^\/&]|&(?!gt;))*\/>/is to match tags

in this case we use (?:[^\/&]|&(?!gt;))* instead of [^\/]*

The first (?:[^\/&]|&(?!gt;))* Matches any character excluding / and &, As the first option, or & if its not followed by gt; i.e. not part of a > symbol as the second option here the (?!gt;) is a negative look ahead assertion (see http://www.php.net/manual/en/regexp.reference.assertions.php) this simply means with out consuming the gt;, insure the next 3 character don’t match this pattern.

The Second simply matches any character that’s not a /.

so the following code

$str = "Mutualism has been retrospectively characterised as ideologically situated between individualist and collectivist forms of anarchism.<ref>Avrich, Paul. ''Anarchist Voices: An Oral History of Anarchism in America'', Princeton University Press 1996 ISBN 0-691-04494-5, p.6<br />''Blackwell Encyclopaedia of Political Thought'', Blackwell Publishing 1991 ISBN 0-631-17944-5, p. 11.</ref> Proudhon first characterised his goal as a "third form of society, the synthesis of communism and property."<ref>Pierre-Joseph Proudhon. ''What Is Property?'' Princeton, MA: Benjamin R. Tucker, 1876. p. 281.</ref> Another is <ref name=rupert/>";
$match = array(
    "/<ref(?:[^\/&]|&(?!gt;))*\/>/is",
    "/<ref[^\/]*>(.*?)<\/ref>/s",);
$str = preg_replace($match,'',$str);
echo $str;

outputs

Mutualism has been retrospectively
characterised as ideologically
situated between individualist and
collectivist forms of anarchism.
Proudhon first characterised his goal
as a “third form of society, the
synthesis of communism and property.”
Another is