The arrivals of Torres and Luiz will serve to bolster a Chelsea squad which captain John Terry has suggested was lacking in depth.

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Krawcheck has a background as a research analyst and has been criticized for lacking the depth of experience that many other CFOs of companies the size of Citi would normally have.

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"To a defense that I think is lacking a little depth right now, it hurts us, " Tortorella said of Stralman's injury.

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Exploring the depth of dependency on particular industrial clusters would be a better measure of where diversification is most lacking.

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