/ @ [ ] In pattern name() = 'sonnet': Root element must be <sonnet>. In pattern @type = 'Shakespearean' or @type = 'Petrarchan': Valid values for the type attribute are "Shakespearean" or "Petrarchan." In pattern count(*) < 4: The <sonnet> element contains a <author> element, an optional <title> element, and a <lines< element. In pattern *[1] = author: The first child of the <sonnet> element must be an <author> element. In pattern (count(*) = 2 and *[2] = lines) or (count(*) = 3 and *[2] = title and *[3] = lines): If you use the optional <title> element, the <sonnet> element must contain the <author>, <title> and <lines> elements in that order. In pattern count(*) < 6: An <author> element must have the elements <lastName>, <firstName>, <nationality> <yearOfBirth> and <yearOfDeath>. (The <yearOfBirth> and <yearOfDeath> elements are optional. In pattern *[1] = lastName: The first child of the <author> element must be a <lastName> element. In pattern *[2] = firstName: The second child of the <author> element must be a <firstName> element. In pattern *[3] = nationality: The third child of the <author> element must be a <nationality> element. In pattern (count(*) = 4 and *[4] = yearOfBirth) or (count(*) = 5 and *[4] = yearOfBirth and *[5] = yearOfDeath): The fourth child of the <author> element must be a <yearOfBirth> element. In pattern count(line) = 14: A sonnet must have 14 <line>s. In pattern count(line) = count(*): The <lines> element can only contain <line> elements.