Suppose that two different types of sources are used in a term paper: books and journal articles. The following UML diagram illustrates how the sources are organized.

First, implement the three classes, Source, Book, and Article, and then write a main method to use them. In the main method, ask the user to enter the number of references, create an array of type Source using the size the user entered, use a loop to ask the user to enter the information for each reference (book or journal article), and then output the contents of each object.

Book publisher: String Source author: String title: String year: int Circle (author: String, title: String, year: int) toString(): String Book (author: String, title: String, year: int, publisher: String) toString(): String equals (aBook: Book): Boolean Article journalName: String pages: String volume: int issue: int Article (author: String, title: String, year: int, journalName: String, pages: String) toString(): String equals (aArticle: Article): Boolean