The 1958 white pages telephone book for La Habana does not list a William Cairns or Patricia Salas, nor does the 1960 Anglo American Directory for La Habana. The main cemetery in La Habana is Cementerio de Colon. Directorio de Familias Cubanas does not list any Cairns/Salas in their post Castro US directory. Did Patricia ever become a US citizen? Did Patricia have any survivor's rights to a US pension or retirement system that William belonged to? Did they have any children? Do you have their, and spouses last names? If Patricia was a US citizen you might want to check the National Archives in College Park Maryland, the records for the US embassy in La Habana are stored there. Jorge Piñón