problema con FK

[huesos52]

Código sql:

CREATE TABLE clientes
(
kx_rut_cliente CHARACTER VARYING(13) NOT NULL,
x_nombre_c CHARACTER VARYING(30),
x_apellido_c CHARACTER VARYING(30),
n_fono_c INTEGER,
CONSTRAINT pk_11 PRIMARY KEY (kx_rut_cliente)
)
 
CREATE TABLE reservas
(
kn_id_reserva INTEGER NOT NULL,
kx_rut_cliente CHARACTER VARYING(13),
n_cantidad_personas INTEGER,
CONSTRAINT reservas_pkey PRIMARY KEY (kn_id_reserva),
CONSTRAINT clientes_fk FOREIGN KEY (kx_rut_cliente) REFERENCES clientes(kx_rut_cliente)
)