Brahma Nand; Tyagi B. B. D. S., . (1965). Co ordinate solid geometry. : .
Brahma Nand; Tyagi B.S Bhu Dev Sharma, . 1965. Co ordinate solid geometry. : .
Brahma Nand; Tyagi B.S Bhu Dev Sharma, . Co ordinate solid geometry. : . 1965.