Endurance Physical -- See Physical fitness Here are entered works on muscular efficiency and physical endurance. Works on optimal physical, mental, and social well-being, as well as how to achieve and preserve it, are entered under Health.
Enemy Aliens -- See Noncitizens Here are entered works on persons who are not citizens of the country in which they reside. When this heading is assigned to works on noncitizens who permanently or temporarily relocate across national borders without complying with the legal requirements of the destination country, the heading Illegal immigration is also assigned.Works on those persons who have no citizenship are entered under Stateless persons.