https://unesdoc.unesco.org/ark:/48223/pf0000154565
https://unesdoc.unesco.org/ark:/48223/pf0000154566
https://periodicos.ufpe.br/revistas/index.php/interritorios/article/view/258971
https://app.box.com/s/a314mhd9aombgatpylekjfdkf3i33n1b