[...] "morpheme structure rules" can be assigned to the phonological component (which they term the "ordering solution" to the duplication problem) [...]. According to the ordering solution, the noninitial members of an obstruent cluser will be 0 for voice and the voicing assimilation rule will spontaneously fill in 0's and alter distinctive plus and minus values.
- Kiparsky (2004), Pag. 164