nonEmpty = xsd:string { minLength = "1" }
start = bibliography
bibliography = element bibliography { bibItem+ }
bibItem = element bibItem { author, articleTitle, journalTitle, volume, issue?, year, pages }
author = element author { surname, forename, initial? }
surname = element surname { nonEmpty }
forename = element forename { nonEmpty }
initial = element initial { nonEmpty }
articleTitle =
    element title {
        attribute type { "article" },
        nonEmpty
    }
journalTitle =
    element title {
        attribute type { "journal" },
        nonEmpty
    }
volume = element volume { xsd:positiveInteger }
issue = element issue { xsd:positiveInteger }
year =
    element year {
        xsd:positiveInteger { pattern = "\d{4}" }
    }
pages = element pages { startPage, endPage }
startPage = element start { xsd:positiveInteger }
endPage = element end { xsd:positiveInteger }