sources..

http://proquest.umi.com/pqdweb?index=1&did=1209294321&SrchMode=1&sid=1&Fmt=3&VInst=PROD&VType=PQD&RQT=309&VName=PQD&TS=1175784445&clientId=8511#fulltext


http://proquest.umi.com/pqdweb?index=2&did=1183576681&SrchMode=1&sid=1&Fmt=3&VInst=PROD&VType=PQD&RQT=309&VName=PQD&TS=1175784445&clientId=8511#fulltext


http://proquest.umi.com/pqdweb?index=10&did=1016235001&SrchMode=1&sid=1&Fmt=3&VInst=PROD&VType=PQD&RQT=309&VName=PQD&TS=1175784656&clientId=8511#fulltext


http://proquest.umi.com/pqdweb?index=19&did=990261811&SrchMode=1&sid=1&Fmt=3&VInst=PROD&VType=PQD&RQT=309&VName=PQD&TS=1175784657&clientId=8511#fulltext


http://proquest.umi.com/pqdweb?index=17&did=1004112171&SrchMode=1&sid=1&Fmt=3&VInst=PROD&VType=PQD&RQT=309&VName=PQD&TS=1175784657&clientId=8511#fulltext



all these are from the proquest from the schools library