Antonio Loría Elena Panteley Arturo Zavala-Río Speed-gradient adaptive high-gain observers for synchronization of chaotic systems. 232-237 2007 ALCOSP https://doi.org/10.3182/20070829-3-RU-4911.00038 conf/alcosp/2007 db/conf/alcosp/alcosp2007.html#LoriaPZ07