Table:
text: Bulgarian International
Previous winners
Previous winners
Year_ Men_s_singles Men_s_doubles Women_s_doubles Mixed_doubles
1985 Heinz Fischer Heinz Fischer Jeliazko Valkov Monika Cassens Kerstin Bohn Thomas Mundt Monika Cassens
1986 Heinz Fischer Thomas Lund Max Gandrup Susanne Pedersen Tanja Berg Thomas Mundt Monika Cassens
1987 Jacek Hankiewicz Peter Buch Jensen Karsten Wolfgang Monika Cassens Angela Michalowski Kai Abraham Petra Michalowsky
1988 Jin Feng Lin Jian Fu Qiang Lin Yanfen Zhang Wanling Li Jian Gao Meifeng
1989 Liang Zhiofang Yu Lizhi Zheng Shouta Lin Yanfen Zhang Wanling Chi Bing Lin Yanfen
1990 Andrey Antropov Andrey Antropov Nikolai Zuyev Diana Koleva Hellene Kirkegaard Nikolai Zuyev Irina Serova

Question: Which men's singles has a Kai Abraham Petra Michalowsky mixed doubles among the Bulgaria internationals?