@incollection{
    kups:02,
    author = "Kupść, Anna",
    title = "The Morphosyntax of {P}olish Verbal Negation: {T}owards an {HPSG} Account",
    crossref = "bro:prz:02:ed"
}
@book{
    bro:prz:02:ed,
    editor = "Brown, Sue and Przepiórkowski, Adam",
    publisher = "Slavica Publishers",
    booktitle = "Negation in {S}lavic",
    address = "Bloomington, IN",
    title = "Negation in {S}lavic",
    year = "2006"
}