We notice, however, that they have included in the text “proofs “of the fundamental congruence theorems but have excluded “proofs “of the fundamental parallel theorems.

DANIEL B. HIRSCHHORN, Why Is the SsA Triangle-Congruence Theorem Not Included in Textbooks?, The Mathematics Teacher, Vol. 83, No. 5 (MAY 1990), pp. 358-361 ...

It is not in accordance with modern views, however, that beginners should be asked to learn the time-honoured proofs for congruence and parallels. Geometry for Beginners, as far as the Theorem of ...