Before entering the new apartment, Fran and Val say the opening lines to the classic Laverne and Shirley. In the same scene it is revealed that their landlord is played by David L Lander, who played Squiggy on Laverne and Shirley.
The apartment Val and Fran rent is clearly the same apartment that Laverne and Shirley shared in their own series.
David L. Lander refers to his significant other as Leonard. Also from Laverne and Shirley ("Lenny and Squiggy").