The public domain consists of all the creative work to which no exclusive intellectual property rights apply. Those rights may have expired, been forfeited, expressly waived, or may be inapplicable. As examples, the works of William Shakespeare and Ludwig van Beethoven, and most early silent films, are in the public domain either by virtue of their having been created before copyright existed, or by their copyright term having expired. Some works are not covered by copyright, and are therefore in the public domain—among them the formulae of Newtonian physics, cooking recipes, and all computer software created prior to 1974. Other works are actively dedicated by their authors to the public domain (see waiver); some examples include reference implementations of cryptographic algorithms, the image-processing software ImageJ (created by the National Institutes of Health), and the CIA's World Factbook. The term public domain is not normally applied to situations where the creator of a work retains residual rights, in which case use of the work is referred to as "under license" or "with permission". As rights vary by country and jurisdiction, a work may be subject to rights in one country and be in the public domain in another. Some rights depend on registrations on a country-by-country basis, and the absence of registration in a particular country, if required, gives rise to public-domain status for a work in that country. The term "public domain" may also be interchangeably used with other imprecise or undefined terms such as the "public sphere" or "commons", including concepts such as the "commons of the mind", the "intellectual commons", and the "information commons".