Some of the entries don't have capital initials, which is why I had A-z rather than A-Z.

You may already be aware of this, but the important thing to remember about the  A-z character class range is that it includes the  [ \ ] ^ _ ` characters as well, and  A-Za-z does not.

sub breakup {
    my $filename = $_[0];
    my $text = $_[1];
    my $re = qr{
(?<apair>
    (?<key>[^:;,\.\s]+)
    \s*
    :
    \s*
    (?<val>[^:;,\.\s]+)
    \s*
    ;
)
|(?<ppair>
    (?<key> \p{Uppercase_Letter}w+ )
    :
    (?<val> \p{Uppercase_Letter}+ )
)
| (?<ppage>  pp\.\s*\d+-\d+\. )
| (?<version3>  \d+\.\d+\.\d+ (?::\d+)? )
| (?<version2>  \d+\.\d+:\d+ )
| (?<year>  \( \d+ \) )
##| (?<name>  (?:  [^\s,\.]+, )+   )
| (?<name>  (?:  \p{Uppercase_Letter}[.\w]+, )+   )
## | (?<title>  (?:[^\s;.,\(\)]+\s*)+[.;,] )
| (?<title>  (?:[^\s;.,\(\)]+\s*){3,} [.;,?!]? )
| (?<comma>,)
| (?<notcommanotspace>[^\s,]+)
| (?<space>\s+)
| (?<other>.)

    }msx;
    my @parts;
    while( $text =~ m{$re}g ){
        my $it   = { %+ };
        next if $it->{space};
        push @parts, $it;
    }
    return \@parts ;
}

__END__
[
  { year => "(1990)" },
  {
    title => "Methods of the Association of Official Analytical Chemis
+ts.",
  },
  { notcommanotspace => "15." },
  { name => "Ed," },
  { comma => "," },
  {
    title => "Association of Official Analytical Chemists Washington;"
+,
  },
  { name => "Dumet," },
  { name => "D.," },
  { name => "Benson," },
  { name => "E.E.," },
  {
    title => "The use of physical and biochemical studies to elucidate
+ and reduce cryopreservation-induced damage in hydrated/desiccated pl
+ant germplasm ",
  },
  { year => "(2000)" },
  {
    title => "Cryopreservation of Tropical Plant Germplasm: Current Re
+search Progress and Application,",
  },
  { ppage => "pp. 43-56." },
  { comma => "," },
  { notcommanotspace => "F." },
  { title => "Engelmann and H." },
  { title => "Takagi " },
  { notcommanotspace => "(eds.)" },
  { apair => "Tsukuba: JIRCAS;", key => "Tsukuba", val => "JIRCAS" },
  { apair => "Rome: IPGRI;", key => "Rome", val => "IPGRI" },
  { name => "Ferreira," },
  { name => "D.F.," },
  {
    title => "An\x{2B69}ses estat\x{ED34}icas por meio do SISVAR para 
+Windows vers\x{4BE0}4.",
  },
  { version2 => "0.1:225" },
  { year => "(2000)" },
  {
    title => "Reuni\x{4BE0}Anual da Regi\x{4BE0}Brasileira da Sociedad
+e Internacional de Biometria,",
  },
  { comma => "," },
  { name => "S\x{4BE0}Carlos," },
  { title => "SP: UFSCAR" },
]
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