Network Coding over wireless networks can provide considerable throughput increase with respect to traditional cooperative relaying strategies at no loss of diversity gain. In this paper, a novel cooperation protocol is developed based on adaptive complex-field wireless network coding. Sources transmit new information symbols linearly combined with symbols previously-estimated from other sources, and weighted using a link adaptive power scaling coefficient. Different from existing wireless network coding protocols, transmissions are not restricted to binary symbols, do not need to be simultaneous, and allow for errors when estimating symbols transmitted from other sources. In a network with N sources, the developed protocol can achieve a throughput up to approximately 1/N symbols per source per channel use, as well as a diversity order of N. Simulated results corroborate the performance analysis of the protocol, showing gains with respect to traditional multi-source cooperation protocols.