@Article{ VELASCO_BERMÚDEZ:399-406,

author = { JOSEFA VELASCO CABRERA and FRANCISCO JAVIER BERMÚDEZ RODRÍGUEZ } ,

title = { SPHERICAL EQUIVALENT AND ASTIGMATISM },

journal = { Atti della Fondazione Giorgio Ronchi },

year = { 1997 },

pages = { 399-406 },

}