Isaack was the brother of Salomon , and they both had sons named Jacob .
According to the Netherlands Institute for Art History ( Dutch abbreviation , RKD ) , Houbraken confused the members of the family Ruysdael .
Isaack was the brother of Ruysdael , and they both had sons named Jacob .
According to the Netherlands Institute for Art History ( Dutch abbreviation , RKD ) , Houbraken confused the members of the family Ruysdael .