@article{01545112,
title = {Newton polygons and formal groups: Conjectures by Manin and Grothendieck.},
journal = {Annals of Mathematics. Second Series},
volume = {151},
year = {2000},
pages = {183-206},
doi = {10.2307/2661381},
zbl = {0991.14016},
language = {en},
url = {http://dml.mathdoc.fr/item/01545112}
}
Oort, Frans. Newton polygons and formal groups: Conjectures by Manin and Grothendieck.. Annals of Mathematics. Second Series, Tome 151 (2000) pp. 183-206. doi : 10.2307/2661381. http://gdmltest.u-ga.fr/item/01545112/