@article {pettit2003effects, title = {Effects of basal sliding on isochrones and flow near an ice divide}, journal = {Annals of Glaciology}, volume = {37}, number = {1}, year = {2003}, pages = {370{\textendash}376}, publisher = {International Glaciological Society}, author = {Erin C Pettit and Jacobson, H Paul and Waddington, Edwin D} }