Where does this current source symbol come from?
I managed to run a reverse Google image search to see where this picture came from. It found it on the Russian translation of Wikipedia. For some odd reason, the English version of this page has somewhat of a different format than the English version.

Here's the Russian Wikipedia page where this picture comes from. You're going to have to use some translator.

But here's what it says about the picture you have provided:

(a) and (b) are common notations for the current symbol. (c) were established by GOST and IEC. GOST is some type of Russian standards for electrical protocols. (d) and (e) are found in foreign literature, though it never says where exactly so it's possible that it's entirely made up for somewhere really obscure and possibly not credible, except for (d). I have seen (d) from plenty of sources as well. I'm not entirely sure why this Wikipedia page says, "Foreign literature" but I have yet to find the origins of (d).

The picture itself is a creation of one's own work meaning that whoever created this picture did not cite where they got this information.

Further investigation utilizing an old handbook it does indeed contain (c) as an ideal current source.