Complex that transfers electrons from reduced plastoquinone to oxidized plastocyanin and translocates protons from the stroma to the lumen. The complex contains a core structure of three catalytic subunits: cytochrome b, the Rieske iron sulfur protein (ISP), and cytochrome f, which are arranged in an integral membrane-bound dimeric complex; additional subunits are present, and vary among different species. [ http://www.ncbi.nlm.nih.gov/pubmed/16228398 http://www.ncbi.nlm.nih.gov/pubmed/16352458 https://www.worldcat.org/search?q=bn%3A0943088399 ]