The first one says to capture everything from the first P of Putative up to but not including the first following semi-colon. Subsequently the whitespace is collapsed.
The second one says to capture everything after "TITLE" and its trailing space(s) up to but not including a newline followed by whitespace followed by "JOURNAL" (which is the following key). Again, subsequently the whitespace is collapsed.
Both of these require the /s modifier. See perldoc perlre for details of the modifiers. You can also fall back on YAPE::Regex::Explain for any regexen that you are having trouble understanding, although it doesn't include support for more modern features, alas.
In reply to Re^3: advance Regex
by hippo
in thread advance Regex
by shabird
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