@article{Stephens1972,
author = {Stephens, R.E.},
title= {Studies on the development of the sea urchin Strongylocentrotus droebachiensis. I. Ecology and normal development},
year = {1972},
doi = {10.2307/1540251},
journal = {Biological Bulletin},
volume = {142},
number = {1},
pages = {132--144},
}