Gw mau tau Rujukan dari Enggang paruh merah utara. Jelasin dalam bahasa melayu

Kemp, A.C. and W. Delport. 2002. Comments on the status of subspecies in the red-billed hornbill (Tockus erythrorhynchus) complex (Aves: Bucerotidae), with the description of a new taxon endemic to Tanzania. Annals of the Transvaal Museum 39: 1–8.

Delport, W., A.C. Kemp, and J.W.H. Ferguson. 2004. Structure of an African Red-billed Hornbill (Tockus erythrorhynchus rufirostris and T. e. damarensis) hybrid zone as revealed by morphology, behavior, and breeding biology. Auk 121: 565–586.