"Butterick 3999; ca. late 1940s; Unprinted Pattern. Men's Sport Shirt: Convertible Collar. This well tailored sport shirt which can be worn outside or tucked-in trousers has short or long cuffed sleeves, convertible collar and two large patch pockets."@en . . "Butterick 3999; ca. late 1940s; Unprinted Pattern. Men's Sport Shirt: Convertible Collar. This well tailored sport shirt which can be worn outside or tucked-in trousers has short or long cuffed sleeves, convertible collar and two large patch pockets."@en . . . "Butterick 3999"@en . . . . .