@incollection{JEDP_2012____A11_0,
     author = {Uhlmann, Gunther},
     title = {Inverse {Problems:} {Visibility} and {Invisibility}},
     booktitle = {},
     series = {Journ\'ees \'equations aux d\'eriv\'ees partielles},
     eid = {11},
     pages = {1--64},
     publisher = {Groupement de recherche 2434 du CNRS},
     year = {2012},
     doi = {10.5802/jedp.94},
     language = {en},
     url = {http://archive.numdam.org/articles/10.5802/jedp.94/}
}