Complex sentence: Two signed letters in Hollandersky's book authenticate a relationship between President Roosevelt and Hollandersky, and include an invitation from the President to visit him at the White House as well as a second letter of reference which acknowledged at least one visit took place around early 1921.
Split into simpler sentences: Two signed letters in Hollandersky's book authenticate a relationship between President Roosevelt and Hollandersky. These include an invitation from the President to visit him at the White House and a second letter of reference which acknowledged at least one visit took place around early 1921.