I found these on the Boone GenWeb site's online cemeteries for Valley Springs Cemetery. What does (Nan) mean? Is J.A. the father of N.A.? And is wife blank because she survived J.A.? What does RF mean?

5. Edwards, J. A. - 20 Mar. 1835 - 23 Apr. 1921 father
N. A. (Nan) - 16 Nov. 1852 - 31 July 1917 wife
6. Edwards, William C. (W. C.) - 1878 - 1906 RF


Thanks.