@article{10_1017_S0017089500030494,
     author = {Carter, Sheila and Ezentas, Ridvan},
     title = {Embeddings of nonorientable surfaces with totally reducible focal set},
     journal = {Glasgow mathematical journal},
     pages = {11--16},
     year = {1994},
     volume = {36},
     number = {1},
     doi = {10.1017/S0017089500030494},
     url = {http://geodesic.mathdoc.fr/articles/10.1017/S0017089500030494/}
}