Etymological character reference
I assume you are talking about the origin and evolution of characters, as opposed to the origin and evolution of the words they represent.  These two are complementary, but not identical.

Analyzing characters and tracing their forms from the oracle bones through Zhou bronzes on into the forms used over 2000+ years of dynastic history is a huge job, and there is no standard work that covers all of this. 

Standard dictionaries such as 漢語大字典 are not specialist works, and will have gaps and weaknesses that you must be careful of, just as the OED is not an authoritative source for tracing the indo-european roots of English.

Rather than look for something that gives you random explanations chosen from unspecified sources, I would recommend that you read Qiu Xigui's book 文字學概要. This has been translated into English as Chinese Writing by Mattos and Norman, and is the best book on the subject in English, by far. This will help you to better understand and evaluate the claims you read.

If you get through that and really want to try reading Chinese works, the Shuowen jiezi 說文解字 of Xu Shen 許慎 remains the indispensible work on the origins and analysis of Chinese characters, and the starting point for all studies of Chinese characters.

Qing dynasty studies of the Shuowen are indispensible adjuncts to raeding Shuowen.  The Shuowen jiezi gulin 說文解字詁林　of Ding Fubao 丁福保 is the most convenient compilation of Qing research. This is pure classical Chinese, with a huge number of special terms and idiosyncratic written forms. I don't think there is a version of this in simplified characters. (Correct me if I'm wrong.)  It does not include all Qing dynasty work on the Shuowen.

Analysis of the original forms of characters also demands knowledge of oracle bone, bronze vessel writing, and the bamboo and silk works that are regularly excavated by archaeologists.  

There are several dictionaries of the oracle bones and bronze characters, but many of these are simply compilations of forms (organized under Shuowen's classification system!), and don't have the kind of explanations you are looking for.  

There is less on the Warring States materials that are now a large and important field of research; there are one or two textbooks I believe, but I'm not familiar enough with this area to recommend anything.

A number of journals, such as 考古 and 中央研究院歷史語言研究所集刊 publish research articles on Chinese characters that try to analyze and identify unfamiliar forms in new works.  These articles regularly overturn long-accepted explanations.

Archaeological document finds are also a major topic for Ph.D. dissertations, both in China and Taiwan.  It generally takes a while for new discoveries and theories from these to work their way into the current literature.

The point of this reply is that character etymology and evolution is a very large area where important work that revises earlier ideas is frequently published. 

I don't think there is one work that can be totally relied on to always have the most current information.  In addition, there are many cases where interpretations are still sharply disputed, so any claims about forms, meanings, or readings should specifically state whose views they are following.