The first photo was from a set listed on a few websites and described only as Italian 1950's. The design is similar to the side chairs shown in the second photo attributed to GESSEF , Consorzio Sedie Friuli (Consortium for the Promotion of Chair Production in Friuli) from the 60's, but I could not find an armchair version. A place to start anyway.
Edit: It looks like GESSEF is just an association a 'la the Danish Furniture Control, not a manufacturer. I believe it's an acronym for Gruppo Esportatori di Sedie Friuli (Group of exporters of chairs of Friuli) . Fratelli Montina was one of its members.
Here's a shot of a GESSEF tag as found on this Montina model 993 chair from the 50's, designed by Studio Tipi.
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