Question: Are Wojciech Fibak and Tom Okker both Polish tennis players?

Context articles: Tom Okker
1981 Suisse Open Gstaad
1980 U.S. Pro Indoor – Doubles
1976 Fischer-Grand Prix
1979 Stockholm Open – Men's Doubles
Wojciech Fibak
1987 CA-TennisTrophy – Doubles
1982 Paris Open
Jan Hajer
1976 British Hard Court Championships

Thomas Samuel Okker (born 22 February 1944) is a former Dutch tennis player.
 He was ranked among the world's top 10 singles players for seven consecutive years, 1968–74, reaching a career high of World No. 3 in 1969.
 He also was ranked World No. 1 in doubles in 1969.
The 1981 Suisse Open Gstaad was a men's tennis tournament played on outdoor clay courts in Gstaad, Switzerland.
 It was the 36th edition of the tournament and was held from 6 July through 12 July 1981.
 The tournament was part of the 1981 Volvo Grand Prix tennis circuit.
 Third-seeded Wojciech Fibak won the singles title.
Wojtek Fibak and Tom Okker were the defending champions, but Okker did not participate this year.
 Fibak partnered Heinz Günthardt, losing in the semifinals.
The 1976 Fischer-Grand Prix was a men's tennis tournament played on indoor hard courts at the Wiener Stadthalle in Vienna in Austria that was part of the 1976 Commercial Union Assurance Grand Prix circuit.
 It was the second edition of the tournament and was held from 25 October through 31 October 1976.
 Fifth-seeded Wojciech Fibak won the singles title.
Wojtek Fibak and Tom Okker were the defending champions, but lost in the final this year.
Wojciech Fibak (popular Wojtek Fibak; born 30 August 1952) is a Polish former tennis player best known for his doubles success with Tom Okker and Kim Warwick, but also for having reached the Top 10 in singles.
The 1987 CA-TennisTrophy was a tennis tournament played on indoor hard courts at the Wiener Stadthalle in Vienna, Austria.
 Ricardo Acioly and Wojciech Fibak were the defending champions but they competed with different partners that year, Acioly with Luiz Mattar and Fibak with Henri Leconte.
 Acioly and Mattar lost in the first round to Mark Dickson and Jorge Lozano, as did Fibak and Leconte to Petr Korda and Diego Nargiso.
The 1982 Paris Open was a Grand Prix men's tennis tournament played on indoor carpet courts.
 It was the 14th edition of the Paris Open (later known as the Paris Masters).
 It took place at the Palais omnisports de Paris-Bercy in Paris, France from 25 October through 1 November 1982.
 Wojciech Fibak won the singles title.
Jan Hajer (born 31 March 1942) is a Dutch former tennis player.
 He was national champion in 1963.
 He won the final by winning over Willem Maris, Dutch National Champion in 1962.
 In 1964 Jan Hajer lost the final of the Dutch National Championship against Tom Okker.
 Later Hajer and Okker represented the Netherlands in the Davis Cup team.
 Hajer had a relative short international tennis career and participated in Wimbledon three times.
 In 1967 he reached the second round which he lost in five sets to Jaidip Mukerjea.
 Hajer and Okker competed in doubles events in South Africa, Philippines and Australia.
The 1976 British Hard Court Championships, also known by its sponsored name Coca Cola British Hard Court Championships, was a combined men's and women's tennis tournament played on outdoor clay courts in Bournemouth, England.
 The men's event was part of the 1976 Commercial Union Assurance Grand Prix.
 The tournament was held from 10 May through 16 May 1976.
 Wojciech Fibak and Helga Masthoff won the singles titles.