{"source":"book","style":"apa","contributors": [{"function":"author","last":"Couch","first":"Leon","middle":"W"} ],"pubtype": {"main": "pubnonperiodical"},"pubnonperiodical": {"title":"Digital and analog communication systems","publisher":"Pearson Prentice Hall","city":"Upper Saddle River, N.J.","year":"2007"},"datasource":"/z-wcorg/","datasource":"http://www.worldcat.org","oclc":"289011660","isbn":"0131424920 9780131424920"}