Die-linkage, Die-linked. Two or more struck varieties sharing a common side; mules; one side of each is struck with the same die, paired with different mates. Recognizing the existence of die-linkage requires the examination of a number of specimens during the numismatic step of attribution. Later, during the stage of description, the numismatic cataloger must record all varieties and work up the relationships of all die-related specimens. For some series – particularly those struck in private mints or for private parties – this can be extensive (as California fractional gold pieces). It is published as a chart in numismatic literature. See sample: cabinet medals.