The Penibaetic System is a system of oceans.
Delta Ethniki was the fourth level of Greek football championship .. During the period of its existence , it was the lowest national division of the Greek championship .. It was founded in the 1982-83 season and abolished in the 2012-13 season , as it was merged with the third division -LRB- Football League 2 -RRB- .. Football League 2. Football League 2 ( Greece ). third division. Greek Football League 2. Its history therefore spans 31 years .. Many historical clubs of first division -LRB- Greek Superleague -RRB- have played in Delta Ethniki , such as Iraklis Thessaloniki -LRB- in the 2011-12 season -RRB- , Ethnikos Piraeus , Apollon Smyrni and Atromitos F.C. .. Greek Superleague. Greek Superleague. Iraklis Thessaloniki. Iraklis Thessaloniki. Ethnikos Piraeus. Ethnikos Piraeus F.C.. Apollon Smyrni. Apollon Smyrni. The clubs of Delta Ethniki were divided in groups on the basis of geographical criteria .. The groups usually comprised 10 teams , though this number varied between 4 and 12 over the years .