@article{10_37236_998,
     author = {Yan Yang and Yanpei Liu},
     title = {Flexibility of embeddings of bouquets of circles on the projective plane and {Klein} bottle},
     journal = {The electronic journal of combinatorics},
     year = {2007},
     volume = {14},
     doi = {10.37236/998},
     zbl = {1158.05316},
     url = {http://geodesic.mathdoc.fr/articles/10.37236/998/}
}