1. Abramson, S., Levin, A., Levin, S., Gur, D.: Window cleaning robot. US Patent App. 15/370,209 (2016)
2. Roumagnac, M.: Pool cleaning robot. US Patent 7,805,792 (2010)
3. Garti, E.: Pool cleaning robot. US Patent App. 11/896,611 (2009)
4. Baek, B.K.: Vacuum cleaner robot. US Patent App. 29/294,635 (2009)
5. Zhang, Y., Zhang, W., Bi, J.: Recent Patents on Mechanical Engineering 10(1), 30 (2017)