Changes in the orbital periods of the eclipsing binaries GS Boo, V442 Cas, and CX Gem are analyzed. It has been shown that variations in the period of each of these systems can be represented by a superposition of the secular decrease and cyclic variations. Cyclic variations in the period can be caused by the presence of a third body in the systems. They can also be a consequence of magnetic activity of the one of GS Boo components and the secondary components of V442 Cas and CX Gem. The secular decrease in the periods of all of these systems can be caused by the angular-momentum loss due to magnetic braking.
A. I. Khaliullina (Sun,) studied this question.