photo_01
type: Photo
has title: Vista Nocturna
has author: author_01
published in: book_02

photo_02
type: Photo
has title: Mapa Ciudad
has author: author_02
published in: book_02

photo_03
type: Photo
has title: Cristales
has author: author_03
published in: book_01

photo_04
type: Photo
has title: Gemas
has author: author_03
published in: book_01

book_01
type: Book
has title: Crystals and Gems
has title: Gemas y Cristales @es
has author: author_01

book_02
type: Book
has title: 1001 Photos
has title: 1001 Fotografías @es
has author: author_02

author_01
type: Author
has first name: Juan
has last name: Pérez

author_02
type: Author
has first name: Pablo
has last name: López

author_03
type: Author
has first name: Francisco
has last name: García