@article{MM2_1996__89_3_156148,
     author = {Nikolaos Askitas},
     title = {Embeddings of 2-spheres in 4-manifolds.},
     journal = {Manuscripta mathematica},
     pages = {35--48},
     publisher = {mathdoc},
     volume = {89},
     number = {3},
     year = {1996},
     zbl = {0859.57034},
     url = {http://geodesic.mathdoc.fr/item/MM2_1996__89_3_156148/}
}