librtlsdr API documentation

Hi I have purchased an RTL2832/R820Tsdr unit from NooElec and I would like to start writing code for an application to decode weather images from satellite APT transmissions on 137 MHz. I already have written an application to decode such images, received by an old analogue FM receiver, but I feel it can be used with the RTL/SDR dongle as well. To do this I need some documentation on the librtlsdr API but I have not found any with my searches. Is there any documentation for librtlsdr API or any other documentation on how to use available funtions in the lib? My thanks in advance. -- Best Regards Neoklis - Ham Radio Call:5B4AZ http://www.5b4az.org/