A definition of strict oscillation of the system of two first-order linear ordinary differential equations is given. It is shown that oscillation follows from strict oscillation of its system, but strict oscillation does not follow. Sturm-type theorems are proven. Oscillatory and strict oscillatory criteria in terms of coefficients of the system are obtained.
"Oscillatory criteria forthe systems of two first-orderlinear differential equations." Rocky Mountain J. Math. 47 (5) 1497 - 1524, 2017. https://doi.org/10.1216/RMJ-2017-47-5-1497