@book{a,
  title = {Foo},
  year = 2021,
  crossref = {b}
}

@book{b,
  title = {Bar},
  author = {Last, First},
  crossref = {b}
}

@inbook{c,
  title = {Baz},
  author = {Family, Given},
  crossref = {b}
}

@article{d,
  crossref = {b}
}

@periodical{e,
  title = "Foo",
  titleaddon = "Bar"
}

@article{f,
  crossref = {e}
}