The maximum weight for a U.S. semi truck and full trailer is 80,000 pounds spread over 18 conventional wheels. Out in the wide-open spaces of Australia, however, road trains can have four trailers and weigh in excess of 300,000 pounds.
Types of academic source. Sources such as newspaper articles, magazine articles, opinion pieces, and websites are not commonly academic, although there are some exceptions. Many journal articles and reports can be found online, for example. Academic journals are very different from popular magazines, although they bear several similarities.
Tertiary Sources. Tertiary sources are the furthest removed from the origin of an event, idea, or period. While secondary sources are the interpretation and evaluation of primary sources, tertiary sources are essentially summaries or collections of primary and/or secondary sources. In simple terms, tertiary sources distill primary and secondary sources into a format that is accessible to a general audience.