SimpleAttribute String {
    name = "String"
}

Class Entry {
    name = "Entry"
    name : String
}

Class First : Entry {
    name = "First"
    lower_cardinality = 1
    upper_cardinality = 1
}

Association Next (Entry, Entry){
    source_upper_cardinality = 1
    target_upper_cardinality = 1
}