sub add_aref_to_sheet {
    my ($aref, $worksheet0) = @_;

    my ($fname, $lname, $title, $supervisor) = @$aref;

    #write data to spreadsheet row by row 

    $worksheet0->write($row++, 2, $fname, $format_HRtop2);
    $worksheet0->write($row++, 2, $lname, $format_HRmiddle);
    $worksheet0->write($row++, 2, $title, $format_HRmiddle);
    $worksheet0->write($row++, 2, $supervisor, $format_HRbottom);
    $row++;

    return $supervisor;
}