This is the bonus cache for the Lab Cache Adventure Советский прото-геокешинг
According to “Espionage Against the United States by American Citizens 1947-2001”:
Between 1950 and 1975, most cases of espionage by Americans that were prosecuted were members of the military services or civilians employed by the military. A shift in policies on prosecuting espionage by Americans in the mid-to-late 1970s, and the enactment of new laws including the Foreign Intelligence Surveillance Act (FISA) and the Classified Information Procedures Act (CIPA), were responsible in part for the threefold increase in espionage cases made public in the 1980s.
Most espionage by Americans has been short-lived and poorly paid. Almost half of American spies received nothing for the risks they took in espionage, usually because they were quickly intercepted before they could transmit information. Over the 50-year period, only four individuals may have received $1 million or more. Regardless of payment, there have been instances of long-term espionage that did serious damage to U.S. interests.
One-fourth of known Americans who tried to commit espionage were intercepted before they could transmit information and were apprehended in the attempt; only one-fifth of known cases lasted 5 years or longer. The number of Americans currently known to have attempted or committed espionage peaked at 35 in 1985, but since then the number per year has been declining to pre-1980s levels.
Americans most consistently have cited money as the dominant motive for espionage, and over time money has increased in predominance among motives. Of individuals who professed a single motive for espionage, one-fourth of civilians but three-fourths of members of the military claimed that they had spied for money. Among volunteer spies, disgruntlement with the workplace was cited as a significant motive: nearly one-fifth of volunteers with a single motive said they had spied from disgruntlement.
This cache is not that the posted coordinates, but should you go there you will be at Robert Hanssen’s signal site code named ELLIS. He would place a piece of tape on the Foxstone Park Sign to tell his handlers that there was something in the ELLIS dead drop. The ELLIS dead drop (a bridge) is no longer there, but just across the street is the replacement bridge and a virtual cache: Spy's Cache (GCD04C). This cache is not far away.
You need to complete the lab cache adventure to obtain the codes needed. Since you can do the lab caches in any order you will need to put the acronyms of the organizations in chronological order, oldest to newest (Wikipedia could be your friend). Once you get the codes in order then plug them into Certitude below separating each code with a forward slash (e.g., AbCz/DyF/tHi/wKLv/mnO) to obtain the final coordinates.
Should be having trouble figuring out how to start the lab cache adventure, try HERE for some help.
You can validate your puzzle solution with certitude.
Congratulations to CasualWalker & 200_laps for the FTF