 Pelham , Henry Francis ( 1911 ) . " Nerva , Marcus Cocceius " . In Chisholm , Hugh . Encyclopædia Britannica 19 ( 11th ed . ) . Cambridge University Press. pp. 393 – 394 . 
 Pelham , Henry Francis ( 1911 ) . " Nerva , Marcus Cocceius " . In Chisholm , Hugh . Encyclopædia Britannica 19 ( 11th ed . ) . Cambridge University Press. pp. 393 – 394 . 
Pelham , Henry Francis ( 1911 ) . " Nerva , Marcus Cocceius " . In Chisholm , Hugh . Encyclopædia Britannica 19 ( 11th ed . ) . Cambridge University Press. pp. 393 – 394 .