@article{10_4153_CJM_2016_039_0,
     author = {\v{S}emrl, Peter},
     title = {Order and {Spectrum} {Preserving} {Maps} on {Positive} {Operators}},
     journal = {Canadian journal of mathematics},
     pages = {1422--1435},
     year = {2017},
     volume = {69},
     number = {6},
     doi = {10.4153/CJM-2016-039-0},
     url = {http://geodesic.mathdoc.fr/articles/10.4153/CJM-2016-039-0/}
}