Harrison, S. P.Geraghty, PaulCarrington, LoisWurm, S. A.2021-11-302021-11-30PL-C94.13http://hdl.handle.net/1885/252028application/pdf© 1986 S. P. Harrisonhttp://creativecommons.org/licenses/by-sa/4.0On the nature of subgrouping arguments198610.15144/PL-C94.13 2021-11-30Attribution-ShareAlike 4.0 International (CC BY-SA 4.0)