Summary:
One may read from a ס"ת which is in the possession of a נכרי, either because it is a ספק ספיקא (according to רש"י) or because it is more likely that a ישראל wrote it (תוס').
And this which was taught that it should be interred; it is this Tannah - והא דתניא יגנז האי תנא הוא
Summary:
It is preferable to cite an anonymous source which is dealing directly with the subject matter, than a specific source which is discussing a tangential issue.
We increase their value up to a Tarp’ik - מעלין בדמיהן עד כדי טרפעיק
Summary:
According to רש"י even for a ס"ת one may pay up to a טרפעיק more, however according to תוספות the addition of (just) a טרפעיק is regarding תו"מ only.