What are some good references for joseki study? Is Ishida's a good investment? I've used kogo's in the past but, is there some way to cross reference pro games?

http://eidogo.com/ gives you references to pro games, which used the selected Joseki.

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My "guide" to become stronger in Go

Never liked Kogo's or Eidogo's portal to it particularly, but I suppose it's a matter of taste. If it works for you great, if not, here are some alternatives:

http://www.brugo.be
http://www.josekipedia.com
http://www.dailyjoseki.com

Don't bother with dictionaries unless you get a database. (Dictionaries have some added value then, but you can get bookish easily while studying from a book - playing a joseki because you learned it etc. If you want to buy a dictionary you can wait a year and buy Takao's instead. Not sure when it will be published in English though, but the German edition will be published next year.)

I second DailyJoseki. It's my main source for looking up joseki sequences.

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We don't know who we are; we don't know where we are.
Each of us woke up one moment and here we were in the darkness.
We're nameless things with no memory; no knowledge of what went before,
No understanding of what is now, no knowledge of what will be.

GoGoD + some search program (I use kombilo). Automatically search for any joseki in pro games. You'd be surprised how many things are called joseki, but never played by pros. You can also look at side joseki, joseki in the context of particular fuseki, etc.

breakfast once said that eidogo is full of errors

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Thanks for the recommendations, daily joseki is awesome!

And so is every other joseki database and even books.
I guess it's best to consult more than one source.

Use both these kinds of sources: 1) Explanations of general principles for josekis. 2) Joseki dictionaries / databases. If you have too much time and generalization skill, then you can try to derive (1) by yourself by studying (2) only. Else read appropriate literature on (1), too. (Besides improve your tactical reading ability.)

What would these be? Something like Davies 38 basic joseki?

I think it is a good place to start. Ishida does this too, but not as consistently and basically.

Whole-Board thinking in Joseki also looks at this, from a slightly different perspective. For example, it helps to build the joseki from principles, depending on what the rest of the board looks like. As a result, it kind of lets you see 'this move is good here because it works with this top corner', and so on. It does less, on the other hand, with explaining why each move inside the joseki is good in general, however.

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Someday I want to be strong enough to earn KGS[-].

38 basic joseki belongs to the (mini selection) dictionary type (2). No. What I really mean for (1) is books like my own one: "Joseki Vol. 1 Fundamentals". Then it becomes much harder to list more such books; the second best for the purpose (1) offer only a fraction and / or are very specialized and often have only very few principles in them. E.g., Positional Judgement by Cho Chikun would be a useful specializing addition, but if you wanted to read such additions, you would want to get dozens of specialized extra books. (Well, reading hundreds of books does help, I can tell you by experience.) But what you really want when studying joseki is books covering this very topic of joseki from the first to the last page. The problem is: Such books with principles are scarce. E.g., Whole Board Thinking teaches by examples only; the best you can do is the same you could do by using a dictionary: extract, compile and organize any possibly contained principles amidst the diagram captions by yourself.

You have yet one other option: Search hard to find principles presented unrelated to joseki but principles that can be used also for joseki. Lucky findings like Go World #41 and Takagawas ideas on using thickness (but you still need to extract the principles by yourself). Then there are the other well known few books with concepts and principles like Strategic Concepts of Go - but what do they tell you about josekis? Little specific.

I have tried hard to find alternatives but the major reason for writing my book might as well have been to fill that gap! Read my book or, if you think it would be too basic for you, wait for volumes 2 and 3!