I live in the US. I am searching for my maternal grandmother who I believe is from the Netherlands. 
Her name is Emmy Muller, and we think she was born around 1940 or 1941. She came to England from the Netherlands and got married in 1960, on May 23rd, in London to my grandfather Mazharul Haque Khan. I have their marriage certificate which I retrieved from UK archives. And I have Emmy Muller's parents names; Henricus Nicholaas Muller, born on 08-12-1902 in Haarlem, died on 20-05-1976 in Leidschendam. He was a bank clerk by profession. Emmy’s mothers' name was Louisa Helena Christiaanse, born on 07-04-1907 in Leiden and died on 22-07-1997 in Haarlem. Henricus and Louisa married on 23-11-1932 in The Hague. 
Emmy had three children from her marriage to my grandfather; one of them is my mother, 

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The first name Louisa = Louise

For possible living persons we have to reckon with privacy law in the Netherlands and elsewhere. For more information the following website gives very good information also in English, https://www.dutchgenealogy.nl/

See also next message, about further help in the Netherlands.

Also possible by contacting website American Red Cross, email-address = intltracing@redcross.org

References to the births of children of H. N. Muller and L. H. Christiaanse, with the first names of the children, and including Emmy, can be found in online newspaper archives, see here (in particular on that list: 1935 and 1941). The third child (with first name) can be found here (by searching for: "h. n. muller") in april 1947. All at the Leiden archives.  [For ease of reference a scan of the 1932 marriage record is here.]

Regarding the eldest sister of Emmy whose names can be found through my previous message, a suggestion might be to consider the signatures of a notice of death on this page and then to go back to this search to check the initials.

See private message