BibTex format
@article{PRETZEL:1995:10.1007/BF01108623,
author = {PRETZEL, O},
doi = {10.1007/BF01108623},
journal = {ORDER-A JOURNAL ON THE THEORY OF ORDERED SETS AND ITS APPLICATIONS},
pages = {135--147},
title = {ORIENTATIONS OF CHAIN GROUPS},
url = {http://dx.doi.org/10.1007/BF01108623},
volume = {12},
year = {1995}
}