TY  - RPRT
TI  - Gradionation: hypothesis for positioning and patterning.
AU  - L E Roth
AU  - D J Pihlaja
PY  - 1977
DO  - 10.1111/j.1550-7408.1977.tb05273.x
UR  - https://pubmed.ncbi.nlm.nih.gov/864624/
ID  - 864624
ER  -