He seems to have quite a number of businesses registered under variations of his name.
Rehka Industries, Inc.
Located in Port Hueneme, CA
Boulevard Cafe, Inc.
Located in Port Hueneme, CA
Re-Kal Industries, Inc.
Located in Thousand Oaks, CA
Robomatic, Inc.
Located in Somis, CA
Sidney Z Rehka is one of the names used.
Found another listing showing Sidney Z Rehka as having died at age 82 in 2010.
Possible relative listed for Sidney Z Rehka is Ingborg Rehka, Inga Rehka, Ingoborg Hozie. (Age 62)
Ancestry - US Public Records, Volume 1 shows her as follows:
Ingeborg Rehka
[Ingoborg Hozie]
Address: PO Box 2096, Porterville, CA, 93258-2096 (1992)
[198 N 2nd St, Porterville, CA, 93257-3873]
[31883 Success Valley Dr, Porterville, CA, 93257-9644 (1995)]
[31883 Success Valley Dr, Porterville, CA, 93257-9644 (1993)]
[PO Box 311, Porterville, CA, 93258-0311]
[38385 Highway 190, Springville, CA, 93265-9516 (1995)]
According to people finder, there is only one person in the US with the name Inga Rehka.