Hello, greetings from Colombia. First of all, huge fan. Searching in the web i find your forum and i search for the database ranking post, and i have to say. Congratulations! You have achieved a big deal. Hope the ATP consider you as a valid source.
Looking at the Open Era in men tennis, i can't find a properly equivalent from the 70's or 80's from ATP Masters 1000 aka. Super 9 that began in 1990. The only close material is a wikipedia page, (Tennis Masters Series records and statistics), that is not accurate. I'm asking you, what database do you use for this tournaments for the 70's and 80's players.
Thanks for your time. And i apologize for my english.