Here is a useful overview paper, by Sun Kwok, about planetary nebulae, and here are some lecture notes about Planetaries by Jacob Arnold:
PNe by jacob arnold.pdf
PNE (1) to print.pdf
You will note that the article by Sun Kwok is from an entire IAU Symposium (S283) in 2011, which was devoted to the latest research on planetary nebulae.
If you go to the website:
http://journals.cambridge.org
and find the "Proceedings of The International Astronomical Union", you will find that you can view and/or download a lot of the "single topic" astronomical symposiums from about 2010 and backwards, in pdf files.
The access policy is remarkably liberal, which is just as well, as the paper volumes of these symposium proceedings cost " a king's ransom"
This is a good way to find out about the current research on "most everything" in astronomy. It is undeniably one of the best resources for bringing you up to speed on the "now" of astronomical research.