dejiny objavov a vynálezov 2 [vynechat] history of discoveries and inventions 2 [vynechat] communication engineering 1 [vynechat] computers 1 [vynechat] electronics 1 [vynechat] elektronika 1 [vynechat] oznamovacia technika 1 [vynechat] počítače 1 [vynechat] radio engineering 1 [vynechat] rádiotechnika 1 [vynechat] television 1 [vynechat] televízia 1 [vynechat] záhadné javy 1 [vynechat] záhady 1 [vynechat]