391. A taxpayer, in computing his cumulative Canadian exploration expenses, shall deduct under paragraph b of section 399 the amount that, at a particular time after 6 May 1974, becomes receivable by him from a person with whom he has made an agreement to unitize an oil or gas field in Canada in respect of Canadian exploration expenses, or Canadian exploration and development expenses or expenses that would have been such expenses if they had been incurred by him after 1971 and before 7 May 1974, incurred by the taxpayer in respect of the whole or any part of that field.
Furthermore, the person having to pay that amount shall, in computing his Canadian exploration expenses, include that amount at that time under paragraph b of section 395.