found: Work cat.: 2002154195: Saunders, N. Oxygen and the elements of group 16, c2003.
found: Britannica online, Nov. 20, 2002(Oxygen group element; also called chalcogen; Group VIa)
found: Encyc. inorganic chem.(Chalcogens)
found: Old catalog heading(Chalcogens)
found: Ox. dict. sci.(Group 16 elements; a group of elements in the periodic table; oxygen, sulphur, selenium, tellurium, and polonium, which all have outer electronic configurations ns²np⁴ with no partly filled inner levels; also called chalcogens)
found: Am. heritage dict.:under Periodic table of the elements (Group 6a)
found: Grant & Hackh's chem.dict(chalcogens: chalkogens)
