Luis Garcia Oliver was a Spanish master portraitist who was born in 1907 and appears to have died in 1977. His works remain popular with collectors, mostly in his home country.
Information on this artist is difficult to find, but the best place to find details about his work would seem to be Spanish art auction sites (most of which can be translated into English without difficulty). Although some of the sites require you to subscribe to find out how much paintings were sold for (such as Arcadja), others are more helpful, especially if they are offering Oliver's paintings for a forthcoming auction (Don Barato).
DonBarato.com is offering a 1967 Oliver Painting For Sale At 15000 Euros!
This however, may be an exception. For the most part, the paintings Luis Garcia Oliver produced in the 1960s, his most popular period, usually command prices of around 500-700 Euros. The work produced by Oliver in the 1940s seem less popular. This painting on offer at Todocoleccion is for sale at only 10 Euros, though it appears to be a reproduction. If you require further details, perhaps contact one of these dealers direct, or possibly enquire of the person who set up Luis Garcia Oliver's entry on findagrave.com who might know more about the artist.
I have been unable to find any information about an artist named Albert Corey. Maybe he was just a local artist who painted for a hobby.
A similar question was asked here back in 2011: http://arts-literature.blurtit.com/3084114/are-luis-garca-oliver-paintings1944-valuable
Here's a brief film with tips on how to find the value of a painting: