In the same place you can find also the collection of Revista Romana de Sah from 1950 until 1990 and also other chess magazines and books - the oldest being from 1872.
Among the chess problem and endgames books which can be downloaded free of charge in PDF format, I mention:
S. Herland - Problemes choisies
Paul Farago - Idei noi in sahul artistic
Anatole F. Ianovcic - Sahul artistic
Emilian Dobrescu & Virgil Nestorescu - Compozitia sahista in Romania
Emilian Dobrescu & Virgil Nestorescu - Studii de sah
Valeriu Petrovici - 75 probleme de sah