The Astronomical Journal
We have analyzed the light curves of four close binary star systems (BV 267, RU UMi, XZ CMi, and VV UMa) using the Wilson-Devinney differential corrections model. The present system geometries of these binaries is that of short-period, semi-detached systems with Roche lobe filling secondaries and main-sequence primaries. Differential coordinates in the mass-luminosity and mass-radius diagrams indicate that the secondary components lie near the main sequence, except in the case of BV 267. It is suggested that these systems are binaries with slightly overluminous and over-sized secondaries which have undergone case A mass transfer. This contention is supported by timing information and qualitatively by the period-frequency relation. These very-nearly contact binaries are likely candidates for post contact system evolution.
Rafert, James Bruce, "Four Short-Period Algols" (1990). Aerospace, Physics, and Space Science Faculty Publications. 224.