@book{ECDL_3,
author = "Σιδηρόπουλος, Νίκος and Χατζηγεωργίου, Νίκος",
publisher = "LibrisTech ΑΕ",
title = "{E}uropean {C}omputer {D}riving {L}icence (ECDL), {Ε}νότητα {A}M5: {Β}άσεις δεδομένων, {Π}ροχωρημένο {Ε}πίπεδο ",
year = "2004",
}