Has_one with :source_type

Rails
1

I am trying to extend the classic example

class Magazine < ActiveRecord::Base
has_many :subscriptions

   has_many  :rental_events ,
        :through => : subscriptions,
        :source => :redaer,
        :source_type => 'Business'

  has_many  :closing_events ,
        :through => : subscriptions,
        :source => :reader,
        :source_type => 'Person'

end

class Subscription < ActiveRecord::Base
belongs_to :magazine
belongs_to :reader, :polymorphic => true
end

class Business < ActiveRecord::Base
has_many : subscriptions, :as => :reader
has_one :magazine, :through => :subcription <---- that’s what I
want , only 1 magazine…
end

class Person < ActiveRecord::Base
has_many : subscriptions, :as => :reader
has_one :magazine, :through => :subcription <---- that’s what I
want , only 1 magazine…
end

I can easily get Person.first.subscriptions, but I cannot get
Person.first.magazine or Business.first.magazine

what’s wrong ? , thanks for your lights …

erwin