Nadi Ravandi, Somayyeh; Haji Zeinolabedini, Mohsen (2013). "Comparison of Used Metadata Elements in Digital Libraries in IRAN with Dublin Core Standard". IJRET : International Journal of Research in Engineering and Technology. V. 2, Issue 3, (March 2013).p. 398 – 403. Available from: http://ijret.org/2013_03_Vol_02_Iss_03.html