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I would suggest that after reading all the basic books on analog circuit design like Allen & Holberg, Gray & Meyer, Laker & Sansen that you try and get a CD which have all the ISSCC, JSSC, CICC and ESSCIRC papers since inception to 2005 which is available from IEEE. If you can really understand everything about advanced op amp topologies there consider you are expert level
Allen Hollberg has beautifully described the design steps involved in designing OP Amps.
Apart from that you can also use the books by Baker and Razavi.
However I feel Allen Hollberg is still the best book to follow.
Allen Hollberg, Baker and few papers are best for designing OP-amp.
from Razavi, we can get analysis part of OP-amp. But I feel Allen Hollberg is the best book( chapter-6,7) to follow the advance Op-amp designing.