@Article{ ACOSTA_PAYÁ:74-76,

author = { MARÍA DOLORES ACOSTA VIGIL and RAFAEL PAYÁ ALBERT } ,

title = { NUMERICAL RADIUS ATTAINING OPERATORS },

journal = { EXTRACTA MATHEMATICAE },

year = { 1987 },

volume = { 2 },

issn = { 0213-8743 },

pages = { 74-76 },

}