Expression of segment polarity genes in brachiopods supports a non-segmental ancestral role of engrailed for bilaterians | Scientific Reports
Segmentation Genes Purpose & Types | What are Gap Genes? - Video & Lesson Transcript | Study.com
Controversies Surrounding Segments and Parasegments in Onychophora: Insights from the Expression Patterns of Four “Segment Polarity Genes” in the Peripatopsid Euperipatoides rowelli | PLOS ONE
Segment Polarity Gene - an overview | ScienceDirect Topics