The phrase "ascertaining those" is correct and usable in written English.
It can be used when referring to the process of determining or finding out specific individuals or items.
Example: "The committee is focused on ascertaining those who are eligible for the scholarship."
Alternatives: "identifying those" or "determining those".
Through direct contacts with the population they have also ascertained those who lost the confidence of the local public.
Sometimes, when they are really young, it's difficult to ascertain those wishes, so we reach out to other professionals.
Interviewing all candidates is important as it will help to ascertain those that are (and those that are not) willing to run the business in the future.
Consequently, the vulnerabilities estimated through robustness analysis can ascertain those by the classical centrality methods when they appear on both analysis results.
A research in this direction could enable companies to be cognizant of their technological capabilities and to ascertain those influential capabilities for which managers should feel quintessential.
THE PRESIDENT: EC-168 is the document, and I wanted to know whether in the course of your investigations you found, you ascertained, those facts, namely, that 70,000 out of 136,000 had died?
Citing the need to get a full picture of the impact of race-blind policies, admissions directors at the University of California at Los Angeles and the University of California at San Diego later admitted they peeked into SAT data in an attempt to ascertain those students' racial backgrounds.
Our big finding was that even if your social media audience is largely made up of people who are also your customers (which in itself can be hard to ascertain), those customers who you actually hear from on social media are not representative of your customers as a whole.
So it's very important to ascertain those views and wishes.
