Credibility for witnesses to incriminate themselves [אין אדם משים עצמו רשע]
Credibility to say, "I lied": Makkot 3a
To say he was bribed financially into signing a document: Ketuvot 18b
To say he was physically threatened into signing a document: Ketuvot 18b
To Say he signed on a false document written to convince others of a person's credit [Amanah]: Ketuvot 19a-b
Power of two witnesses
Combining two Witnesses who testify separately: Ketuvot 26b
Two are equal to 100 contradictory witnesses: Yoma 83a; Temurah 27b
Regarding witness testimony we automatically accept two witnesses, but where we are investigating reality we go by the majority of those we consult: Yoma 83a
When we have one witness testifying against a set of two witnesses: Ketuvot 19b, 22b
Verbal testimony reporting written testimony
Where it was written at the time of the deed, to aid recollection: Ketuvot 20a
Above, if he wouldn't remember on his own: Ketuvot 20a
Faulty Testimony
"Old" Testimony: Ketuvot 20b
Splitting testimony into a valid segment and an invalid segment: Gittin 8b
Credibility to bring witnesses, after having brought several sets of witnesses who were proven to be lying: Makkot 5b
Returning to provide more testimony - כיון שהגיד שוב אינו הוזר ומגיד
The (in-)validity of testimony provided after completing an initial round of testimony: Makkot 3a
In contradicting one's signature witnessing a Bill: Ketuvot 18b, 19b
