我是sql新手。我试着运行sqlschema，下面是代码的一部分

create table PageColours (
    id          serial,
    userID      serial references  users(id),
                --references users(id),
    isTemplate  boolean default'false',
    name        NameValue not null unique,
    primary key (id)
);

create table People (
    id          serial,
    email       EmailValue not null unique,
    givenName   NameValue not null,
    familyName  NameValue,
    invitedID   serial references Events(id),
    attendedID  serial references Events(id),

    primary key (id)
);

create table users(
  id        serial
            references People(id),
    passWord    varchar not null,

    BillingAddress  serial not null
                    references Places(id),
    HomeAddress     serial
                    references Places(id),
    ListID          serial
                    references ContactLists(id),
    ColorID         serial
                    references PageColours(id),
    primary key (id)

);

它回来了 [2020-07-03 15:28:19] [42P01] ERROR: relation "people" does not exist ```
[2020-07-03 15:28:19] [42P01] ERROR: relation "users" does not exist

实际上，所有外键引用表引用都不存在。当我删除引用时，就可以创建表了，有人能帮我吗？