Dermal ridges data (monozygotic twins)
Data on dermal ridge counts in left and right hand in (nuclear) families
Data on dermal ridge counts (left and right hand) in 18 monozygotic twin pairs.
Sarah B. Holt (1952). Genetics of dermal ridges: bilateral asymmetry in finger ridge-counts. Annals of Eugenics 17 (1), pp.211–231. DOI: 10.1111/j.1469-1809.1952.tb02513.x