OHMS
Governmental reforms and liberalism have led to
Rutherford Birchard Hayes has those initials.
Theodore Roosevelt
Cabinet initials since 1979 are HHS.
None. The only president close to those initials is JFK- John Fitzgerald Kennedy
Length
pump priming
CFS= Cerebral Spinal Fluid
The initials I-J indicate colour when describing a 'white' diamond, and indicate the diamond is slightly yellow.
Reference initials in a memo are typically used to indicate who typed or prepared the memo. They are placed at the bottom of the memo, after the writer's initials or signature. Reference initials provide a record of who created the document.
provenance
Did you mean "alphabet agencies"? It's a term for governmental departments that are usually known by their initials, such as IRS, NASA, etc.
I'm uncertain what the initials "FED" might mean, but the initials "NSF" stand for non-sufficient funds.
It is superlfuous to give reference initials if they only tell you that the author of the letter was also the typist. Such initials are only of interest if the typist was another person than the author.
CTIA: Cellular Telecommunications and Internet Association. This is an multi-national non-governmental association that represents mobile communications carriers.
Someone can learn and practice on provenance by finding out information about it. A person can go to the library or a bookstore and find books about practicing on provenance.
The initials FRS can stand for a number of things from a school to governmental entities to science, technology and transport acronyms. Some of the possibilities are The Federal Reserve System, the title Fellow of the Royal Society, Family Radio Service and Fuel Recommended Surcharge.