I understand not wanting to put such a long lined input file in CODE tags; but, in the future, please at least note that the entire file is a single line.

Assuming that each pair of <ref> and its matching </ref> tags are always on a single line in the files you want to process, this seems simpler:

Code:

awk -F'<ref>' '
{	for(i=2; i<=NF; i++)
		print substr($i, 1, match($i, "</ref>") - 1)
}' file.txt

As long as the text files really are text files (i.e., with no lines longer than LINE_MAX bytes including the terminating <newline> character), this should work with any awk utility. (But, as always, on Solaris/SunOS systems, change awk to /usr/xpg4/bin/awk.)