An encyclopedia article also often includes many maps and illustrations, as well as bibliography and statistics. Four major elements define an encyclopedia: its subject matter, its scope, its method of organization, and its method of production:  Some works entitled "dictionaries" are actually similar to encyclopedias, especially those concerned with a particular field (such as the "Dictionary of the Middle Ages", the "Dictionary of American Naval Fighting Ships", and "Black's Law Dictionary"). The "Macquarie Dictionary," Australia's national dictionary, became an encyclopedic dictionary after its first edition in recognition of the use of proper nouns in common communication, and the words derived from such proper nouns. There are some broad differences between encyclopedias and dictionaries. Most noticeably, encyclopedia articles are longer, fuller and more thorough than entries in most general-purpose dictionaries. There are differences in content as well. Generally speaking, dictionaries provide linguistic information about words themselves, while encyclopedias focus more on the thing for which those words stand. Thus, while dictionary entries are inextricably fixed to the word described, encyclopedia articles can be given a different entry name. As such, dictionary entries are not fully translatable into other languages, but encyclopedia articles can be. In practice, however, the distinction is not concrete, as there is no clear-cut difference between factual, "encyclopedic" information and linguistic information such as appears in dictionaries. Thus encyclopedias may contain material that is also found in dictionaries, and vice versa. In particular, dictionary entries often contain factual information about the thing named by the word. Information in traditional encyclopedias can be assessed by measures related to such quality dimension as authority, completeness, format, objectivity, style, timeliness and uniqueness. Encyclopedias have progressed from written form in antiquity, to print in modern times. Today they can also be distributed and displayed electronically. One of the earliest encyclopedic works to have survived to modern times is the "Naturalis Historiae" of Pliny the Elder, a Roman statesman living in the first century AD. He compiled a work of 37 chapters covering natural history, architecture, medicine, geography, geology, and other aspects of the world around him. He stated in the preface that he had compiled 20,000 facts from 2000 works by over 200 authors, and added many others from his own experience. The work was published around AD 77–79, although Pliny probably never finished editing the work before his death in the eruption of Vesuvius in AD 79.