@incollection{11933,
author = {Robert Gulliver and Walter Littman},
title = {{Chord uniqueness and controllability\,:\,the view from the boundary / I}},
series = {Contemporary mathematics},
volume = {268},
booktitle = {Differential geometric methods in the control of partial differential equations},
editor = {Robert Gulliver},
publisher = {American Math. Soc.},
address = {Providence, RI},
year = {2000},
pages = {145--176},isbn={0-8218-1927-5},
}