matrix completion, positive semidefinite matrix, partial matrix
Graphs and linear algebra (matrices, eigenvalues, etc.) (msc 05C50), Positive matrices and their generalizations; cones of matrices (msc 15B48)
Logistics (theme 3)
North-Holland
Linear Algebra and its Applications
Networks and Optimization

Laurent, M. (1997). The real positive semidefinite completion problem for series-parallel graphs. Linear Algebra and its Applications, 252, 347–366.