@article{v005a007,
 author = {Lance Fortnow},
 title = {A Simple Proof of Toda's Theorem},
 year = {2009},
 pages = {135--140},
 doi = {10.4086/toc.2009.v005a007},
 publisher = {Theory of Computing},
 journal = {Theory of Computing},
 volume = {5},
 number = {7},
 URL = {http://www.theoryofcomputing.org/articles/v005a007},
}