61.189
(b) A flight instructor must maintain a record in a logbook or a separate document that conatins the following:
(1) The name of each person whose lookbook or student pilot certificate that instructor has endorsed for solo flight privileges, and the date of the endorsement: and
(2) The name of each person that instructor has endorsed for a knowledge test or practical test, and the record shall also indicate the kind of test, the date, and the results.
(c) Each flight instructor must retain the records required by this section for at least 3 years.
The question I will throw in is that 61.197 says that to renew your CFI you can present a record showing that in 24 months you have had 5 or more students endorsed for a practical test with an 80% pass rate.
What records will suffice for proving this? Copies of 8710 forms with a copy of the passed temp airman cert?