Kirilov, M., et al. Chemistry and Environmental Protection Grade 9. Sofia: Bulvest 2000, 2003 320 p. : il. 954-18-0350-4.
Kirilov, M., et al. Chemistry and Environmental Protection Grade 9. Sofia: Bulvest 2000, 2003 320 p. : il. 954-18-0350-4.
Kirilov, M., et al. (2003) Chemistry and Environmental Protection Grade 9, Sofia: Bulvest 2000 320 p. : il. 954-18-0350-4.
Kirilov, M., & et al. (2003). Chemistry and Environmental Protection Grade 9. English Language Schools. Sofia: Bulvest 2000, 320 p. : il.
Kirilov M, et A. Chemistry and Environmental Protection Grade 9: English Language Schools. Sofia: Bulvest 2000; 2003. p. 320 p. : il. ISBN: 954-18-0350-4.