@article {Astley:1993:0736-2935:221, title = "Wave envelope element formulations for exterior acoustic problems: Status and projections", journal = "INTER-NOISE and NOISE-CON Congress and Conference Proceedings", parent_itemid = "infobike://ince/incecp", publishercode ="ince", year = "1993", volume = "1993", number = "6", publication date ="1993-08-24T00:00:00", pages = "221-224", itemtype = "ARTICLE", issn = "0736-2935", url = "https://ince.publisher.ingentaconnect.com/content/ince/incecp/1993/00001993/00000006/art00035", keyword = "13.1.5, 23.1", author = "Astley, R.J. and Macaulay, G.J. and Coyette, J.P.", abstract = "", }