I recently purchased a vintage (1970) Kelek mechanichal chronograph. Prior to purchasing the watch, I briefly researched the brand, and found out that they supplied movements to Breitling.
After purchasing the watch, I was able to get a copy of the article "Kelek - Selfwinding chronographs against all odds", published in the Europa Star magazine in 1995. Copy of the article attached for those with an interest in this somewhat obscure manufacturer. Two years after this article was published, Kelek was taken over by Breitling and renamed Chronometrie Breitling. An electronic copy of the article was provided by Europa Star free of charge.
Enjoy the read.