@book{ ROSALES_GARCÍA:181,

author = { JOSE CARLOS ROSALES GONZALEZ and PEDRO ABELARDO GARCÍA SÁNCHEZ } ,

title = { NUMERICAL SEMIGROUPS },

publisher = { SPRINGER },

address = { NUEVA YOURS, ESTADOS UNIDOS },

year = { 2009 },

pages = { 181 },

isbn = { 978-1-4419-01 },

}