public function filter_by_author_letter($letter, $firstnamefirst = false) {
        $field = self::get_fullname_field($firstnamefirst);
        $this->filter_by_letter($letter, $field);
    }
public function filter_by_author_letter($letter, $firstnamefirst = false) {
        $field = self::get_fullname_field($firstnamefirst);
        $this->filter_by_letter($letter, $field);
    }
public function filter_by_author_letter ( $ letter , $ firstnamefirst = false ) { $ field = self :: get_fullname_field ( $ firstnamefirst ) ; $ this -> filter_by_letter ( $ letter , $ field ) ; }
Filter the author by letter.

@param string  $letter         The letter.
@param bool    $firstnamefirst Whether or not the firstname is first in the author's name.
Filter the author by letter .