foreign keys - script

I'm also having a problem with my references.

In the script below, I get this error after each references statement:
NOTICE:  CREATE TABLE/FOREIGN KEY clause ignored; not yet implemented

Any ideas?

drop table model_part;
drop table models;
drop table parts;
drop table category;
drop sequence model_part_model_part_id_seq;

create table category (
        category_id char(5) primary key,
        name varchar(20));

create table parts (
        part_id char(10) primary key,
        category_id char(5) references category
                on delete cascade,
        name varchar(20),
        price numeric(7,2));

create table models (
        model_id char(10) primary key,
        name varchar(20),
        description text);

create table model_part (
        model_part_id serial,
        part_id char(10) references parts
                on delete cascade,
        model_id char(10) references models
                on delete cascade);

Adam Lang
Systems Engineer
Rutgers Casualty Insurance Company