//Declares an element "announcement" //Containing the following sequence of elements //distribution,head,more_info,courses //Declares an element "course" //Containing the following atributes (instructor=string,number=NMTOKEN) //Declares an element "courses" //Containing the following sequence of elements (course=unlimited number) //Declares an element "distribution" //Containing the following sequence of elements (to,from) //With atribute (category=(string, required)) //Declares an element "from" //Declares an element "head" //Containing the following sequence of elements (subject,notice) //Declares an element "courses" //Containing the following sequence of elements (website=choice) //Declares an element "courses" //Declares an element "courses" //Declares an element "courses" //Declares an element "courses"