[texhax] bibliography problem

[Ricardo Franklin Mergarejo]

Dear LaTeX user's

I´m written my thesis and I had trouble with the bibliography. I´m uisng 
the natbib and the references in the text had a unwanted tilde (~) between 
the name and the surnname. And when in the .bib file I had several authors, 
the main author is at the end of the list in the references. How can I fix 
that?

Thanks in advances

Ricardo Franklin Mergarejo.
Instituto Superior de Tecnologia y Ciencias Aplicadas
Quinta de los Molinos
Ave. Salvador Allende y Luaces
Ciudad de la Habana. Cuba
Apartado Postal 6163
Telef : (537) 785018 y 797858