Due to information from the linked page, Bravo! Records started in 1957. The first advertisment can be found in Billboard 11. Sept. 1961 page 33 beneath the then new company name Pickwick International, Inc., while early label versions sometimes denotes the old company version Pickwick Sales Corp.
The information is confusing. One source denotes the label changed in 1960 to International Award Series, the advertisement had gone on, as can be proved by the link above.
There was a wild mix of versions with sometimes other label of the Pickwick family stickered on the cover and several labels included. See for example Pedro And His Amigos - Holiday In South America, that incl. an International Award Series label.
The documentation here at discogs is poor till now, so please try to add full sets of images and add all identifiers, to state 'one' clear version, as the guides ask for.
Used on LPs in the US and 7" EPs (and for some time into the early 1970s, cassette and 8-Track tapes) in Britain. Ultimately folded into the parent label by 1968.
Note: US LP releases have a K (mono) or KS (stereo) prefix before the catalog number. KX was a christmas series.
UK EPs start with a BR prefix .
The Both Sides Now Publications website research reveals the below information regarding Bravo Records (http://www.bsnpubs.com/pickwick/bravo.html).
Bravo Records was a label of Pickwick Sales (1959-62), later Pickwick International, and manufactured by the K.M. Corporation (probably the Keel Manufacturing Corporation), a part of the Pickwick empire. It was originally in Freeport, Long Island, New York. The series started at number K-100, and ran to number 158. At that point, the label name changed to International Award Series, perhaps due to a conflict with another label with the same name.
Bravo had different labels for their mono and stereo releases. They were both black, but the mono label had gold print and the stereo label had silver print.