. "Problems and exercises"@en . "Problems and exercises" . "Chemical calculations : a systematic presentation of the solution of type problems, with 1000 chemical problems arranged progressively according to lesson assignments"@en . . "Chemical calculations : a systematic presentation of the solution of type problems, with 1000 chemical problems arranged progressively according to lesson assignments" . . . "Chemical Calculations : a systematic presentation of the solution type problems, with 1000 chemical problems arranged progressively according to lesson assignments"@en . . . . . . . . . . "Chemical calculations a systematic presentation of the solution of type problems, with 1000 chemical problems arranged progressively according to lesson assignments"@en . "Chemical calculations; a systematic presentation of the solution of type problems, with 1000 chemical problems arranged progressively according to lesson assignments" . "Chemical calculations; a systematic presentation of the solution of type problems, with 1000 chemical problems arranged progressively according to lesson assignments"@en . . . "Chemical calculations. A systematic presentation of the solution of type problems, with 1000 chemical problems arranged progressively according to lesson assignments"@en . . . . . .