On the Minimum Rank Among Positive Semidefinite Matrices with a Given Graph.
Matthew BoothPhilip HackneyBenjamin HarrisCharles R. JohnsonMargaret LayLon H. MitchellSivaram K. NarayanAmanda PascoeKelly SteinmetzBrian D. SuttonWendy WangPublished in: SIAM J. Matrix Anal. Appl. (2008)