Solovei I.V., Khutinaeva M.A., Chelysheva L.A., Rodionov A.V., Gaginskaya E.R.
Lampbrush sex bivalent of the birds: Identification and structure.
Tsitologiia — 1990. — V. 32, — P. 816–824.

The avian lampbrush chromosome discribed earlier as a univalent was shown to be an asymmetrical bivalent formed by Z and W sex chromosomes. The morphology of the ZW bivalents in the oocytes of pigeon and domestic fowl was studied by light microscopy. The results of our morphological studies of the sex chromosomes (=lampbrushes) of domestic fowl were compared with literary data on banding and synapsis of these chromosomes.