Aleksandrova N. I. , Shulga T. I. : Study of volitional qualities of schoolchildren with the help of the "unsolvable problem" procedure 87'6 p.130
Belous V. V. , Shul'ga T. I. :
Practical assistance to school psychologist (in Russian)
92'1 p.168
Shul'ga T. I. :
The problem of volitional regulation in ontogenesis
94'1 p.105