@article{BASM_2023_1_a0,
     author = {Jaume Gin\'e and Jaume Llibre},
     title = {Criteria for the nonexistence of periodic orbits in planar differential systems},
     journal = {Buletinul Academiei de \c{S}tiin\c{t}e a Republicii Moldova. Matematica},
     pages = {3--7},
     publisher = {mathdoc},
     number = {1},
     year = {2023},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/BASM_2023_1_a0/}
}