I linked some entries on the Blue Macaws website

Entries on the blue macaws (in Latin) in Monographia Psittacorum by Johann Georg Wagler published in Munich in 1832.
Entry on Hyacinthine Macaw in Descourtilz's Ornithologie brésilienne published between 1854 and 1856.
Excerpts from Wallace's Narrative of Travels on the Amazon and Rio Negro published in 1853.
EEP studbook report for 1997.