# Source code for sphinxcontrib.bibtex.style.referencing.extra_label

    from dataclasses import dataclass, field
    from typing import TYPE_CHECKING, Iterable, List

    from sphinxcontrib.bibtex.style.template import entry_label, reference

    from . import BaseReferenceStyle, BracketStyle

    if TYPE_CHECKING:
        from pybtex.richtext import BaseText
        from pybtex.style.template import Node

    @dataclass
    class ExtraLabelReferenceStyle(BaseReferenceStyle):
        """Reference just by label."""

        #: Bracket style.
        bracket: BracketStyle = field(default_factory=BracketStyle)

        def role_names(self) -> Iterable[str]:
            return ["label", "labelpar"]

        def outer(self, role_name: str, children: List["BaseText"]) -> "Node":
            return self.bracket.outer(
                children,
                brackets="par" in role_name,
                capfirst=False,
            )

        def inner(self, role_name: str) -> "Node":
            return reference[entry_label]