@article{01687749,
title = {Differential geometry in the space of positive operators.},
journal = {Bolet\'\i n de la Asociaci\'on Matem\'atica Venezolana},
volume = {6},
year = {1999},
pages = {125-139},
zbl = {1028.58003},
language = {en},
url = {http://dml.mathdoc.fr/item/01687749}
}
Recht, Lázaro. Differential geometry in the space of positive operators.. Boletín de la Asociación Matemática Venezolana, Tome 6 (1999) pp. 125-139. http://gdmltest.u-ga.fr/item/01687749/