See also the following sources:

▎ENGLISH

RNA folding:

Eddy 2004 How do RNA folding algorithms work?
https://www.nature.com/articles/nbt1104-1457

Useful tools:
RNA fold
http://rna.tbi.univie.ac.at/cgi-bin/RNAWebSuite/RNAfold.cgi

Rfam database
https://rfam.xfam.org

Eterna - RNA folding RNA science game
https://eternagame.org