Կաղապար:Greenwood&Earnshaw
Greenwood Norman N., Earnshaw Alan (1997)։ Chemistry of the Elements (2nd ed.)։ Butterworth-Heinemann։ ISBN 0-08-037941-9
Greenwood Norman N., Earnshaw Alan (1997)։ Chemistry of the Elements (2nd ed.)։ Butterworth-Heinemann։ ISBN 0-08-037941-9