To jog a bit our memories let's not forget that explicit expressions for friction factors for flows through non circular duct cross-sections, as well as for helices, spirals, tube banks (with tubes in line or staggered, bare or finned), granular beds, etc., have also been published.
Colebrook's article had no bibliography. He provided references to his previous work and one on dimensional analysis by Scoby via footnotes, but gave no details to help find the work of the Prandtl, von Karmen, Taylor and Nikuradse. He also gives credit for the idea of combining the “smooth law” and “rough law” in this article to C. M. White, who is a co-author on Colebrook's previous work.
