Source:http://linkedlifedata.com/resource/umls/id/C1167072
GO: The outer, i.e. cytoplasm-facing, lipid bilayer of the nuclear envelope; continuous with the endoplasmic reticulum of the cell and sometimes studded with ribosomes. [ISBN:0198547684],NCI: The nuclear envelope has two membranes, each with the typical unit membrane structure. They enclose a flattened sac and are connected at the nuclear pore sites. The outer nuclear membrane is continuous with the rough endoplasmic reticulum (ER) and has ribosomes attached. (NCI)