Collar, N. J. 1997. Family Psittacidae (Parrots). in del Hoyo, J., Elliot, A. and Sargatal, J. eds. Handbook of the Birds of the World. 4. Sandgrouse to Cuckoos: 280-477: Lynx Edicions, Barcelona (for Psittacus intermedia and Trichoglossus haematodus)
Collar, N. J. 1997. Family Psittacidae (Parrots). In del Hoyo, J., Elliot, A. Sargatal, J (eds.) Handbook of the Birds of the World. 4. Sandgrouse to Cuckoos: 280-477: Lynx Edicions, Barcelona. [voor Psittacus intermedia en Trichoglossus haematodus]