I too am looking for an Anna Sjogren, sister to Johan Ludvig Sjogren and daugher of Theodor Sjogren. The information I have says they lived in Stockholm. Johan immigrated in 1902 with his wife and two children and settled in Wisconsin. Family lore says Anna lived in Bellingham, Washington but I have no information on who she married. Let me know if any of this sounds like it fits your Anna.
Laura