2. Web OPAC (International Library Catalogue):

National Library Singapore	http://catalogue.nlb.gov.sg/cgi-bin/spydus.exe/MSGTRN/EXPNOS/NLBHOME?HOMEPRMS=NLBGENPARAMS
Library of Congress	http://catalog2.loc.gov/
Melvyl: The Catalogue of the University of California Libraries	http://melvyl.worldcat.org/
National Library of Australia	http://catalogue.nla.gov.au/
National Library of Medicine (NLM),USA	http://www.ncbi.nlm.nih.gov/nlmcatalog
The British Library	http://explore.bl.uk/primo_library/libweb/action/search.do?dscnt=1&dstmp=1389697884211&vid=BLVU1&fromLogin=true#
The World Largest Library Catalogue	http://www.worldcat.org/
The European Library Catalogue	http://www.theeuropeanlibrary.org/tel4/
National Library of Scotland	http://main-cat.nls.uk/vwebv/searchBasic?sk=nls_en
University of Macau Library	http://umaclib3.umac.mo/