+}
+
+=head2 GetVariationsOfISBN
+
+ my @isbns = GetVariationsOfISBN( $isbn );
+
+ Returns a list of varations of the given isbn in
+ both ISBN-10 and ISBN-13 formats, with and without
+ hyphens.
+
+ In a scalar context, the isbns are returned as a
+ string delimited by ' | '.
+
+=cut
+
+sub GetVariationsOfISBN {
+ my ($isbn) = @_;
+
+ return unless $isbn;
+
+ my @isbns;
+
+ push( @isbns, NormalizeISBN({ isbn => $isbn }) );
+ push( @isbns, NormalizeISBN({ isbn => $isbn, format => 'ISBN-10' }) );
+ push( @isbns, NormalizeISBN({ isbn => $isbn, format => 'ISBN-13' }) );
+ push( @isbns, NormalizeISBN({ isbn => $isbn, format => 'ISBN-10', strip_hyphens => 1 }) );
+ push( @isbns, NormalizeISBN({ isbn => $isbn, format => 'ISBN-13', strip_hyphens => 1 }) );
+
+ # Strip out any "empty" strings from the array
+ @isbns = grep { defined($_) && $_ =~ /\S/ } @isbns;
+
+ return wantarray ? @isbns : join( " | ", @isbns );
+}
+
+=head2 GetVariationsOfISBNs
+
+ my @isbns = GetVariationsOfISBNs( @isbns );
+
+ Returns a list of varations of the given isbns in
+ both ISBN-10 and ISBN-13 formats, with and without
+ hyphens.
+
+ In a scalar context, the isbns are returned as a
+ string delimited by ' | '.
+
+=cut
+
+sub GetVariationsOfISBNs {
+ my (@isbns) = @_;
+
+ @isbns = map { GetVariationsOfISBN( $_ ) } @isbns;
+
+ return wantarray ? @isbns : join( " | ", @isbns );