Toni Ruottu, 20.2.2013
problem: The reader can not check the original source for details.
solution: Always provide enough information for the reader to lookup the original work. For example in the essay "Common Quotation Problems" Toni Ruottu encourages you to "Always provide enough information for the reader to lookup the original work." When this essay was published that essay was available from http://www.cs.helsinki.fi/u/twruottu/overlay2013/problems.html.
problem: The reader does not know which parts were written by you. If you don't have any quotation marks it is assumed you wrote everything yourself, as having refereces without quotes only refer your inspiration, and not the source of the writing.
solution: Always put text written by other people inside quotation marks. For example: Toni discusses using direct quotation without quotation marks and states that "The reader does not know which parts were written by you."
problem: The reader does not know how you modified the original text. It is assumed that you did not modify the original text at all.
solution: Always mark edits with square brackets. For example: Toni points out that "[when] you don't have any quotation marks it is assumed you wrote everything yourself [...]".
problem: The reader does not know how you interpret the quote.
solution: Always write your own interpretation in addition to the direct quote. You might want to leave the direct quote out entirely unless you think your interpretation might be wrong. If you think your interpretation might not be correct, do provide some analysis on alternative interpretations.
problem: Translating is a lossy process and the original way of presenting the idea might not be that good anyway.
solution: Be critical when you read scientific manuscripts. Also, have self-confidence. Writing about scientific topics in an understandable way is really hard. The generations before you were probably not able to come up with the best possible way of presenting the idea you are striving to describe.